CEl26P
NOTES:
• Some of tape recorders may not operate properly owing
to different specification or electrical characteristics
affected by signal distortion, electrical noise, level drop-
out caused after long years of use.
• When using the tape recorder fitted with the mixing
feature, it needs to disable the mixing function for both
recording and playback.
• Depending on the tape recorder used, better reading
result may be attained when the red plug is unplugged
from the MIC jack.
• As
it
may impede proper data transfer and verif'lCation
depending on the position of the volume control, tone
control, bass contral, and treble controI, try to find the
optimum level by varying their positions.
4. CIRCUIT DESCRIPTION
The CE-126P has two microprocessors; the P-CPU by which
data traosfer is carried out with the host CPU (M-CPU) and
the printer control PCU. Since the host CPU (PC-1245,
1250, 1251, 1401, (EL5500) have different CPU actions,
the CE-126P CPU therefore performs different action.
M-CPU to P-CPU data transfer method (for PC-1245, 1250,
1251)
, OEYICE SELECT,
SELI
~:
B"'SY~
_r-u---'
:10)_ ..... _. ~
,,---
.
,
.
ACL ' ACL
ACK~
.
PCU1t"".
DWT
~'f'-----
4-1.
What action should the P-CPU take prior to data transfer is
dependent on thestate of SEL1 and SEL2 from the M-CPU.
(DEVICE SELECT)
4-2.
SEL1 SEL2 Action
L L Nop
LHPCU select
HLRemote ON
HHACl
The following actions take place before data transfer.
(1) SEL 1 goes low and SEL2 high.
(2) BUSY trom the M-CPUturns high level.
(3) Upon receipt of BUSY, ACK of the P-CPU is set high
and the data is received to the p·CPU.
Since the data
is
transferred in bit by bit serial mode,
above steps (2) and (3) are repeated eight times to complete
transfer of one data. For instance, those steps are repeated
for 192 times (24 x 8) in order to transfer a 24 digits data.
The print command, however, is sent out to the P-CPU at
the end of the data in a form of the code "00"
4-3.
M-CPU to P-CPU data transfer method (for PC-1401,
EL5500)
Since there are no SEL1 and SEL2 used for the PC·1401
and EL5500, DEVICE SELECT is dependent on the
contents of data.
(UEYlca SELECT)
SOUT
_j, ~ __.
= ....._........__
J
t
:~ ;--V"\
L
DOUT
(1) For DEVICE SELECT, XOUT becomes high.
(2)
As
the P-CPU receives a high state of XOUT, it sends
ACK to the M-CPU.
(3)
As
the M-CPU receives ACK, it sends back BUSY.
(4) Oata is received to the P-CPU with a high state of
BUSY. ACL, REMOTE ON, CPU select actions is
carried out depending on the contents of data.
4-4. Print data transfer
(DATA 11IAHSPORTATlOH)
SOUT
IIlJSY
__.,f!_._.IL_,
ACI! /\
I
~
I.
Bl1'1I1I
:~
XOUT goes low when the print data is transferred. Data
transfer
is
done in a manner identical to those of the PC-
1250.
-2-
