Sharp ER-A440 Service Manual page 20

3) SSP register access method
Access to SSP break address register is performed through the tem-
porary register as shown below:
Temporary
1
Enable flags can be accessed individually.
Though enable register
brake address registers and
writing to brake address register
Therefore, set and to temporary, then write into
Since the temporary register is commonly used by BAR sets, thefol-
lowing register setting is performed after completion ofsetting of each
break address register.
SSP control method
Access to the enable register and the brake address register is only
possible when writing to them from the CPU.
bit 7
6 5 4
0 0 0 CMP4
7. PRINTER control circuit
1) Block diagram
Address bus
Data
CPU
bus
2) General description of the printer controller
The DP-730 is used as the R/J printer. The printer mechanical timing
control is made by the CPU through MPCA7.
A19 A18 A17 A16 A15
Temporary
WR
can be accessed individually, writing to
is performed at the same time as
through the temporary register.
3 2 1 0
CMP3 CMP2 CMP1 CMP0 (FFFFFFH)
RECEIVER
DRIVER
MPCA7
Fig. 7-1
A8 A7
2
Fig. 6-5
Information on which brake register the SSP brake is detected in is
read as binary data by reading address FFFFFFH (*1).
Used in an expanded register.
Normally is a reserve bit. Whenreading, fixed to 0.
at last. If there are 32 break registers, binary expression is made with the
above 5 bits, and 0th is "00000
When detected simultaneously by two or more break registers,
onewith the smaller BAR number is read as binary data.
The brake signals (NMI) and the above detection data (CMP0~4)
areheld until the above detection data are read. So read should be-
made in the NMI sub routine. (Clear by FFFFFFH read.)
1: FFFFFFH is not fulldecoded. (FFFF00H~FFFFFFH). There-
fore,unnecessary read access in parentheses should not be
performed.
3) Printer motor drive circuit
MPCA7
PRINTER
(DP-730)
DP
When the MTD is high, the motor rotates.
When the MTD is low, the motor stops.
4 – 13
A2
EN
WR
3
" and 31st is "11111
B
Main PWB side
+24V
C227
MTD
COM
MTD
2.2K
R128 R127
C92
4
."
B
Printer side
M
Speed limiter
circuit
DP
Q7
Normal 555µs (516~590µs)