Real-Time Output Port Control Registers; Port Mode Register 12 Format; Real-Time Output Port Mode Register Format - NEC PD78052 User Manual

20.3 Real-Time Output Port Control Registers

The following three registers control the real-time output port.
• Port mode register 12 (PM12)
• Real-time output port mode register (RTPM)
• Real-time output port control register (RTPC)
(1) Port mode register 12 (PM12)
This register sets the input or output mode of port 12 pins (P120 through P127) which are multiplexed with
real-time output pins (RTP0 through RTP7). To use port 12 as a real-time output port, the port pin that performs
real-time output must be set in the output mode (PM12n = 0: n = 0 to 7).
PM12 is set by using a 1-bit or 8-bit memory manipulation instruction.
This register is set to FFH by RESET input.
Symbol 7 6 5
PM12 PM127 PM126 PM125 PM124
(2) Real-time output port mode register (RTPM)
This register selects the real-time output port mode/port mode bit-wise.
RTPM is set with a 1-bit or 8-bit memory manipulation instruction.
RESET input sets this register to 00H.
Figure 20-4. Real-time Output Port Mode Register Format
Symbol 7 6 5
RTPM RTPM7 RTPM6 RTPM5
Cautions 1. When using these bits as a real-time output port, set the ports to which real-time output
is performed to the output mode (clear the corresponding bit of the port mode register
12 (PM12) to 0).
2. In the port specified as a real-time output port, data cannot be set to the output latch.
Therefore, when setting an initial value, data should be set to the output latch before
setting the real-time output mode.
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CHAPTER 20 REAL-TIME OUTPUT PORT
Figure 20-3. Port Mode Register 12 Format
4 3 2 1 0
PM123 PM122 PM121 PM120
4 3 2 1
RTPM4 RTPM3 RTPM2 RTPM1 RTPM0
Address After Reset
FF2CH FFH
PM12n Selects I/O mode of P12n pin (n = 0 to 7)
0 Output mode (output buffer ON)
1 Input mode (ourput buffer OFF)
After
0 Address
Reset
FF34H 00H
RTPMn Real-time Output Port Selection (n = 0 to 7)
0 Port mode
1 Real-time Output Port Mode
R/W
R/W
R/W
R/W