Hitachi AP1 Data Book page 245

4-bit single-chip microcomputer
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----------------------------------------------------------------HMCS404C
Table 15. TIMER-B Interrupt Request Flag
TIMER-B Interrupt
Request Flag
o
Interrupt Request
No
Yes
Table
16.
TIMER-B Interrupt Mask
TIMER-B Interrupt
Mask
o
• INPUT/OUTPUT
I nterrupt Request
Enable
Disable (Mask)
The MeU provides 58 Input/Output pins, and they are con-
sist of 32 standard pins and 26 high voltage pins. Each standard
pin may have one of three mask options: (A) "Without pull-
up MOS (NMOS open drain)", (8) "With pull-up MOS", or
(C) "CMOS". And also each high voltage pin may have one
of two mask options: (D) "Without pull-down MOS (pMOS
Pull up MOS
(e)
approximately
40kn
to
160kn
NMOS(A)
open drain)", or (E) "With pull-down MOS". As pull-down
MOS is connected to internal V
disp
line, select RAl
IV
dmp pin
as V
disp
with mask option when at least one high voltage pin is
selected as "With pull-down MOS" option.
When any Input/Output common pin is used as input pin, it
is necessary to select the mask option and output data as shown
in Table 18.
• Output Circuit Operation of Standard Pins with ''With pull-
-up MOS" Option
Fig. 15 shows the circuit used in the standard pins with
"with pull-up MOS"option.
8y execution of the output instruction, the write pulse will
be generated, and be applied to the addressed port. This pulse
will turn "ON" the PMOS (8) to make the transient time
shorten to obtain "High level", if the output data is changed
from "0" to "1". In this case, the "write pulse" allows the
PMOS (8) to tum "ON" as long as 1/8 instruction cycle. While
"write pulse" is "0", pull-up MOS (C) may retain the output
in high level.
The HLT signal becomes "0" in stop mode, so that MOS (A)
(8) (C) tum "OFF".
Write pulse
(Output
.---f--------
instruction)
t----+-------9"--
HL T
Data
1 Instruction cycle
~I
Output instruction execution
Write pulse
___ ----'n'----_
Fig. 15 Output Circuit Operation of Standard Pins with "with Pull-up MOS" OPtion
243

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