Schroff Shelf Alarm Panel (SAP) SAP PCA9555
21596-077
www.schroff.biz 4 R1.0, February 05, 2008
6 SAP PCA9555
The PCA9555 device:
• controls the status of the LEDs
• reads the status of the Telco Alarm Cutoff push button (CLEAR)
• controls the Telco Alarm relays
Table 1: SAP PCA9555 Device Function
D
6.1 SAP I²C Addresses
Table 2: SAP I²C Addresses
6.2 User definable LEDs
The LEDs USER (1, 2, 3) are user definable and connected to the I²C-bus I/O
port of the PCA 9555 on the SAP.
PCA9555 I/O pins Function State
0.0 Power Alarm to telco relays output 1 = relays powered
0.1 Minor Alarm to telco relays output 1 = relays powered
0.2 Major Alarm to telco relays output 1 = relays powered
0.3 Critical Alarm to telco relays output 1 = relays powered
0.4 N/C Pulled High
0.5 LED_MIN (Minor alarm LED) output 1 = On
0.6 LED_MAJ (Major alarm LED) output 1 = On
0.7 LED_CRIT (Critical alarm LED) output 1 = On
1.0 Alarm cutoff push button input 0 = push button pushed
1.1 Minor Clear input 0 = voltage applied to input pins
1.2 Major Clear input 0 = voltage applied to input pins
1.3 N/C Pulled High
1.4 N/C Pulled High
1.5 LED_USER3 output 1 = On
1.6 LED_USER2 output 1 = On
1.7 LED_USER1 output 1 = On
LM75 SEEPROM PCA9555
0x96/0x4b 0xa6/0x53 0x44/0x22
