Bit Sequential Buffer Control Register - NEC PD789860 User Manual

12.3 Bit Sequential Buffer Control Register

The bit sequential buffer is controlled by the following three registers.
• Bit sequential buffer output control register 10 (BSFC10)
• Port mode register 2 (PM2)
• Port 2 (P2)
(1) Bit sequential buffer output control register 10 (BSFC10)
BSFC10 controls the operation of the bit sequential buffer.
This register is set with a 1-bit or 8-bit memory manipulation instruction.
RESET input clears this register to 00H.
Figure 12-2. Format of Bit Sequential Buffer Output Control Register 10
Symbol 7 6
BSFC10 0 0
BSFE10
0 Operation disabled
1 Operation enabled
(2) Port mode register 2 (PM2)
PM2 sets port 2 to input/output in 1-bit units.
When using the P20/TMO/BSFO pin as a data output of the bit sequential buffer, clear the PM20 and P20
output latch to 0.
This register is set with a 1-bit or 8-bit memory manipulation instruction.
RESET input sets this register to FFH.
Symbol 7 6
PM2 1 1
PM20
0 Output mode (output buffer on)
1 Input mode (output buffer off)
CHAPTER 12 BIT SEQUENTIAL BUFFER
5 4 3
0 0 0
Bit sequential buffer operation control
Figure 12-3. Format of Port Mode Register 2
5 4 3
1 1 1
P20 pin input/output mode
User's Manual U14826EJ5V0UD
2 1 <0> Address After reset
0 0 BSFE10
2 1 0 Address After reset
1 PM21 PM20
R/W
FF60H 00H R/W
R/W
FF22H FFH R/W
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