Programmable I/O Ports - Renesas M16C/62P Series Hardware Manual

M16C/62P Group (M16C/62P, M16C/62PT)

24.12 Programmable I/O Ports

If a low-level signal is applied to the NMI pin when the IVPCR1 bit in the TB2SC register = 1 (three-phase output
forcible cutoff by input on NMI pin enabled), the P7_2 to P7_5, P8_0 and P8_1 pins go to a high-impedance state.
Setting the SM32 bit in the S3C register to "1" causes the P9_2 pin to go to a high-impedance state.
Similarly, setting the SM42 bit in the S4C register to "1" causes the P9_6 pin to go to a high-impedance state.
The input threshold voltage of pins differs between programmable input/output ports and peripheral functions.
Therefore, if any pin is shared by a programmable input/output port and a peripheral function and the input level at
this pin is outside the range of recommended operating conditions VIH and VIL (neither "high" nor "low"), the
input level may be determined differently depending on which side-the programmable input/output port or the
peripheral function-is currently selected.
When changing the PD14_i bit (i=0 to 1) in the PC14 register from "0" (input port) to "1" (output port), follow the
procedures below.
(1) Set P14_i bit
(2) Change PD14_i bit to "1" by MOV instruction
Indeterminate values are read from the P3_7 to P3_4, PD3_7 to PD3_4 bits by reading the P3 and PD3 registers
when the PM01 to PM00 bits in the PM0 register are set to "01b" (memory expansion mode) or
"11b"(microprocessor mode) and setting the PM11 bit to "1".
Use the MOV instruction when rewriting the P3 and PD3 registers (including the case that the size specifier is ".W"
and the P2 and PD2 registers are rewritten).
When the PM01 to PM00 bits are rewritten, "L" is output from the P3_7 to P3_4 pins during 0.5 cycles of the
BCLK by setting the PM01 to PM00 bits in the PM0 register to "01b" (memory expansion mode) or "11b"
(microprocessor mode) from "00b" (single-chip mode) after setting the PM11 bit to "1".
Rev.2.41 Jan 10, 2006
REJ09B0185-0241
http://www.xinpian.net
Page 377 of 390
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Setting Procedure
:MOV.B #00000001b, PC14 ; P14_i bit setting
:MOV.B #00110001b, PC14 ; Change to output port
24. Precautions
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