HD6432621 Hitachi, HD6432621 Datasheet - Page 315

• Manufacturer Part Number: HD6432621
• Description: (HD64F262x Series) 16-Bit Microcomputer
• Manufacturer: Hitachi

Port E MOS Pull-Up Control Register (PEPCR)
PEPCR is an 8-bit readable/writable register that controls the MOS input pull-up function
incorporated into port E on an individual bit basis.
When a PEDDR bit is cleared to 0 (input port setting) with 8-bit bus mode selected in modes 4 to
6, or in mode 7, setting the corresponding PEPCR bit to 1 turns on the MOS input pull-up for the
corresponding pin.
PEPCR is initialized to H'00 by a reset, and in hardware standby mode. It retains its prior state in
software standby mode.
9.9.3
Port E pins also function as data bus input/output pins (D7 to D0). If at least one of areas 0 to 7 is
designated as 16-bit bus space in modes 4 to 6, port E pins automatically function as data bus
input/output pins. If all areas are designated as 8-bit bus space in modes 4 to 6, or in mode 7, each
pin in port E functions as an input/output port, and input or output can be specified individually
for each pin. Port E pin functions are shown in table 9-19.
Table 9-19 Port E Pin Functions
Pin
PE7/D7,
PE6/D6,
PE5/D5,
PE4/D4,
PE3/D3,
PE2/D2,
PE1/D1,
PE0/D0
Bit
Initial value :
R/W
Pin Functions
:
:
Selection Method and Pin Functions
The pin function is switched as shown below according to the operating mode,
ABWCR in the bus controller, and PEDDR.
Operating mode
ABWCR
PEnDDR
Pin function
PE7PCR PE6PCR PE5PCR PE4PCR PE3PCR PE2PCR PE1PCR PE0PCR
R/W
7
0
R/W
6
0
PEn input
0
R/W
5
0
H'FF
Modes 4 to 6
PEn output
R/W
1
4
0
input/output
(D7 to D0)
R/W
Not H'FF
Data bus
3
0
—
R/W
2
0
PEn input
—
0
R/W
Mode 7
1
0
PEn output
n = 7 to 0
—
1
R/W
0
0
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