RTZ STC-1200 Guide

RTZ Professional Audio, LLC
Alpharetta, GA USA
Web: http://www.rtzaudio.com
Email: [e-mail]
COPYRIGHT © 2019, RTZ PROFESSIONAL AUDIO, LLC
RTZ® IS A REGISTERED TRADEMARK OF RTZ PROFESSIONAL AUDIO, LLC DOC-REV-A02
02/12/2020
–
STC-1200
SEARCH TIMER CONTROLLER
AMPEX MM-1200 UPGRADE
Owner’s Manual and User Guide

Contents
1INTRODUCTION ...................................................................................................................................3
1.1 Description ....................................................................................................................................3
1.2 Overview .......................................................................................................................................3
1.3 Installing the STC-1200 Board......................................................................................................3
1.4 DIP Switch Configuration ..............................................................................................................5
1.5 Initial Machine Power Up ..............................................................................................................6
1.6 Tape Roller Quadrature Encoder Signal Waveforms ...................................................................6
2Command Line Interface .......................................................................................................................7
3Web Server Interface.............................................................................................................................8
3.1 Network Connection......................................................................................................................8
4FIRMWARE UPGRADE via BOOTLOADER.......................................................................................13
4.1 Enabling the STC-1200 bootloader.............................................................................................13
4.2 LMFLASH Installation and Serial Port Configuration..................................................................14
4.3 Select Binary Image and Program Address................................................................................15
4.4 Downloading the Binary Image...................................................................................................16

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1 INTRODUCTION
Thank you for purchasing your new STC-1200 search/timer/communications controller for Ampex MM-1200
studio recorders! All controller cards are tested individually prior to shipping. Before installing the card,
please read this document thoroughly and retain it for future reference. Additional copies of this manual are
available for a nominal printing fee or may be downloaded from our website at http://www.rtzaudio.com.
All items are carefully packed to endure the rigors of shipping and handling. However, please inspect all
contents and packaging immediately upon receipt. Please report any problems to us immediately. In the
event of damage, retain all shipping and packaging materials for shipper damage claims inspection.
1.1 Description
The STC-1200 is an advanced search/timer and communications controller designed around the latest
ARM 32-bit microprocessor technology. The STC-1200 controller uses a Tiva TM4C1294NCPDTI3 32-bit
M4 ARM processor by Texas Instruments
1
that is designed for use in advanced motion control and
communication systems applications. The STC-1200 provides auto-locator search/cue functions and
provides several communications subsystems that provide TCP/IP, web server, RS-232, RS-422 and MIDI
communications support.
The controller firmware runs under Texas Instruments TI-RTOS operating system. TI-RTOS brings true
multi-threaded real-time programming power to ARM embedded systems. The auto-locator task runs at
highest priority and manages all cue point search and store functions. In addition, the DRC-1200 wired
remote provides a true hardware remote control with OLED display and user interface buttons for transport
control and auto-locator functions.
1.2 Overview
The STC-1200 card will only work in machines that have been upgraded with the DTC-1200
transport controller board. Refer to the DTC-1200 Installation Guide for the required DTC wiring
modifications necessary for DTC and STC operation. The DTC upgrade wiring modifications adds serial
communication links between the two boards. This allows the DTC and STC to send commands and
exchange data between the locator and transport controller subsystems in real time as needed.
No external connections are required to use the STC in its most basic form. The single cue point
store/locate buttons on the transport deck work just like the original Ampex locator functions. This single
point memory is dedicated the deck locate button functions and is separate memory from the other ten
locate points used by the locater remote. Thus, a tape operator could use this single locate point on the
deck for his/her own purposes if needed and not affect any locate points stored by the remote.
1.3 Installing the STC-1200 Board
Confirm the 5V system power is set at the correct voltage. When adjusting the 5V power, it’s best to
measure the voltage at the control card cage edge connector. The wiring harness add some inline
resistance due to resistance in the wire between the power supply and control card cage. Thus, a slight
drop will be seen measuring 5V at the machine power supply test point verses at the control card cage
edge connector. The incoming 5V to the STC should not exceed 5.1V or damage may occur to
components on the STC and/or DTC boards. Note you can also measure the 5V voltage level on the STC
card via test point TP4 on the STC card. Power down the machine, remove the original Ampex timer/cue
card from the machine and install the STC-1200 card in the machine.
1
Texas Instruments is a legal trademark of Texas Instruments Corporation.

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Figure 1 - PCB Connector and Feature Items
1. Spare accessory RS-422 serial link port. Currently this port is unused and available for future
communications, control and/or linking support.
2. BOOT switch used to activate bootloader during system resets. Hold the BOOT switch while
simultaneously pressing the RESET switch to activate the bootloader.
3. Micro-SD memory card connector. Currently the web server style sheets and other files are
stored on this drive. Do not remove this memory card from the board.
4. Ethernet 100 MB connector port. Connect a wire from your local Ethernet network hub to this port
to use the web server remote/configuration interface.
5. DIP configuration settings switch. Refer to the DIP switch configuration section for a description of
the switch functions.
6. JTAG programmer/debugger connection interface for the Tiva series processors. This port is
used to flash firmware and debug code from the Tiva JTAG M4 ARM debugger.
7. System RESET switch. The main processor on the STC board is reset when this switch is
pressed.
8. RS-232 serial port COM1. Normally this port is for TTY command line interface. It is also used for
flashing firmware with the bootloader when the bootloader is activated.

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9. RS-232 serial port COM2. This port is reserved for future system expansion use.
10. DRC-1200 wire remote power and RS-422 communications port. This port is dedicated for use by
the DRC-1200 wired remote only.
11. MIDI I/O board connector interface. A ribbon cable runs from this connector to the MIDI I/O
connector board mounted in the machine somewhere.
12. Real time clock backup battery. This requires a CR1632 type 3V lithium coin cell battery that
powers the real time clock module when the machine is not powered up.
13. ISP programming connector for ATMEGA88 7-segment display driver processor. This is used to
flash the firmware that drives the 7-segment display on the transport deck.
14. This connector provides an I/O OPTION port for future expansion daughter cards. A daughter
card can be added to provide the master 9600 Hz time base and allow for variable speed control.
1.4 DIP Switch Configuration
The DIP switch allows setting the COM1 serial port baud rate and whether or not to enable the port for
the DRC remote. If the DRC wired remote is not connected, the port should be disabled so the controller
is not continuously spewing high speed display data out the unterminated transmit data lines on the port
connector and emitting clocking noise potentially.
Table 1- DIP Switch Configuration
DIP SWITCH S1 SETTINGS
SWITCH
FUNCTION
CS1
This switch sets RS-422 data rate to the DRC1200 remote port. The BAUD rate is
set for 1.5Mbs if in ON positions. Otherwise the speed is set to 400Kbs in the
OFF position. The DRC-1200 remote speed must be set to match this setting.
The default speed is set to 1.5Mbs for fastest display refresh, but longer runs of
cable or noisy environments may require slower speed if packet errors occur.
CS2
This switch enables the RS-422 serial port for the DRC-1200 remote in the ON
position. If the DRC wired remote is not connected to the remote port, this switch
should be set to the OFF position.

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1.5 Initial Machine Power Up
Install the STC board in the card cage rear slot connector J4. Power up the machine and confirm the 5V
power is correct at test point TP4 on the STC board. Check the tape timer 7-segment display is working
correctly by rolling the tape roller by hand. The time display should increment in seconds as the roller
spins forward.
The quadrature signals must be adjusted properly in order for the tape position timer to work properly and
accurately. Some machines have sensor gain adjustment trimmers in the timer roller /display housing.
The quadrature signals from the roller encoder must be properly adjusted with the A/B encoder signals 90
degrees out of phase with each other.
1.6 Tape Roller Quadrature Encoder Signal Waveforms
The tape roller quadrature encoder signals are 5V logic and may be monitored with an oscilloscope at
TP9 (PHA) and TP7 (PHB) on the STC controller board. The signals must be 90 degrees out of phase
when the roller spins as shown below in Figure 2. The quadrature encoder works as described in the
Ampex MM-1200 owner’s manual. Refer the Ampex manual for the adjustment procedures for the roller
quadrature encoder phototransistors and LED’s if needed. Later model machines may have gain
adjustment trimmers in the timer roller assembly itself.
Figure 2 - Quadrature Encoder A/B Waveforms
If the tape timer appears to be inaccurate, confirm that the PHA and PHB signals of the quadrature
encoder match as shown above in shuttle mode and adjust if necessary.

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2 Command Line Interface
The STC provides a serial command line interface on serial port COM1 at baud rate 115,200. Connect a
serial port terminal emulator (eg, TeraTerm) to this port to access the command line interface. Enter the
command help to see a list of valid commands.
Note the command ipaddr may be used to display the TCP/IP address assigned to the machined from a
DHCP server. The Ethernet port must be connected to a network with a DHCP server available. Usually,
the DHCP server resides in a cable modem or router/gateway.
Figure 3 –TTY Command Line Interface

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3 Web Server Interface
The web server maybe accessed from most any modern browser on smart phones, tablets and desktop
computers. This simple interface allows configuration and basic remote control, but no real-time tape time
display is available on the remote web page. However, basic transport and locate functions can still be
used to control the machine.
3.1 Network Connection
The STC requires a DHCP server available on the network. Usually, most cable modems or routers in
home and small business networks provide the DHCP server services. Consult the documentation for
your cable modem or router for more information on enabling and configuring the DHCP server. Most
systems will have this enabled by default so computers in your home network can automatically acquire
an IP address to assign to all of the machines and network devices connected to your local network.
When the STC boots, it attempts to connect to a DHCP server and request an IP address to assign to the
STC board. Once this address is assigned, clients on the local network can then connect with most any
modern browser to this IP address.
Use the command line interface and execute the ipaddr command to obtain the IP address assigned to
the machine. Then, type this address into a browser on your local network to access the STC web server
pages.

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Figure 4 - Web Server Home Page
This is the home page of the STC web server. Basic information about the machine and STC status is
shown here during normal operation.

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Figure 5 - Web Server Configuration Page
This is be basic STC parameter configuration page. Settings may be stored or reset from this page to
change configuration settings.

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Figure 6 - Web Server Remote Page
This is the basic transport remote control web page. Here you can control the transport and locator for
basic machine use. The interface allows storing and locating to any of the ten cue point memory locations
shared by the DRC-1200 wired remote. Either interface may be used to control the machine.

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4 FIRMWARE UPGRADE via BOOTLOADER
All STC-1200 controller boards ship with bootloader firmware installed in the first 16K of flash memory
space starting at address 0x0000. The first 16KB of code space is reserved exclusively for the bootloader
firmware in the STC-1200 design. The main transport controller firmware resides just after the 16KB
bootloader area at hex address 0x4000 (16384).
The processor always begins execution with the bootloader at power up or anytime a system reset is
issued. The bootloader checks for presence of the transport controller firmware by doing a blank check of
the application firmware code space. If no code is found, it automatically enters in the bootloader
download state waiting for firmware download data packets via the COM1 serial port on the STC-1200.
Otherwise the bootloader checks the status of the BOOT switch at boot time and enters the bootloader
download state if the switch is pressed during a system reset. In normal boot mode the bootloader
transfers execution to address 0x4000 and begins normal execution of the application firmware. Note that
COM1 is also used for the STC’s TTY command line interface during normal application execution.
The computer used to download the firmware must have a standard RS-232 port available. Most
computer motherboards have a single RS-232 connector header on the board. Refer to your computer
motherboard documentation for RS-232 port information. You may also use a RS-232-to-USB serial
converter if your PC or laptop does not have a RS-232 port available.
4.1 Enabling the STC-1200 bootloader
Connect the RS-232 serial cable from the PC to the COM1 serial port on the STC as shown in Figure 7.
Then, press and hold the BOOT switch S2 (located behind the SD drive socket) and simultaneously press
the RESET button S3 to active the boot loader. The STC board will reboot and turn the STAT LED off to
indicate it’s ready to begin receiving firmware download data via the COM1 serial port.
Figure 7 - COM1 Serial Port Connection
The bootloader indicates ready state by turning off the STAT LED. The STC-1200 board is now ready to
accept downloading via the COM1 serial port at 19,200 BAUD.

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4.2 LMFLASH Installation and Serial Port Configuration
LMFLASH is a free application from Texas Instruments that allows downloading firmware updates to the
STC-1200 via the COM1 RS-232 serial port on the STC-1200. You may need to create an account at
ti.com to download this utility. The LMFLASH link is also on the RTZ Audio website.
Make sure no other applications are using the serial port (usually COM1) prior starting LMFLASH. You
must close any instances of TeraTerm prior to using LMFLASH or the COM1 serial port will be locked.
Start the LMFLASH application and set the serial port settings as shown below on the configuration tab.
The serial port must be configured for 19,200 BAUD (e.g. 19200,N,8,1). Be sure to disable the Auto
Baud Support option as shown below in Figure 8.
Figure 8 - LMFLASH Serial Port Settings

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4.3 Select Binary Image and Program Address
Next select the new STC-1200 binary firmware image to be flashed on the board. The latest binary
firmware images are available at our rtzaudio.com website. The STC-1200 binary image will generally be
named STC1200_TivaTM4C1294NCPDT.bin and should be placed on your local computer with
LMFLASH installed. You may want to make a backup copy of this file in the event it’s needed in the future
for some reason.
Warning, you must set “Program Address Offset” to 4000 as shown below. Failure to set the
program address to 4000 may overwrite the bootloader. In this case, a JTAG programmer must be
used to re-flash the bootloader into the processor flash memory.
Figure 9 - Binary File Image Selection

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4.4 Downloading the Binary Image
Once the binary image and program address is set to 4000, the LMFLASH is ready to begin downloading.
First, check that the STC-1200 is ready with the bootloader activated and ready to receive the new
firmware image. The STC and should be waiting with the STAT1 LED off indicating the bootloader is
ready to receive a new download. Then, click the Program button in LMFLASH to begin downloading the
new firmware image to flash.
Once programming begins, the STAT LED will blink as each package of data is received and written to
flash. The status bar of the LMFLASH application shows the progress of the download/flash operation.
Once the process completes, restart the processor via the RESET button or power cycle the machine to
begin executing the new firmware.
If the download fails to start, check that the serial port is connected and set correctly. The LMFLASH
application serial port baud rate must be set to 19,200 baud in order to communicate with the bootloader.
Figure 10 - Downloading Binary Image