NEC PD75402A - Manual (Page 62)

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CHAPTER 5. PERIPHERAL HARDWARE FUNCTIONS
5.1.5 Internal Pull-up Resistors
The
µ
PD75402A can incorporate internal pull-up resistors for all port pins except P00 and P10. The
µ
PD75P402
can incorporate internal pull-up resistors for all port pins except P00, P10, and P50 through P53.
As shown in Table 5-4, internal pull-up resistors can be specified by software or by a mask option (although
specification by mask option is not possible on the
µ
PD75P402).
The pull-up resistor specification register which specifies internal pull-up resistors for ports 0 through 3 and 6
(POGA) is an 8-bit write-only register. Its format is shown in Fig. 5-7. POGA is set by an 8-bit write instruction. Reading
and bit manipulation is not possible. RESET input clears this register to zero.
Internal pull-up resistor specification for port 3 is valid only for input pins specified as in input mode. The status
of pins specified as in output mode is “without pull-up resistor” irrespective of the POGA setting.
Table 5-4 Internal Pull-Up Resistor Specification for Each Port
Port (Pin Name) Internal Pull-Up Resistor Specification Method Specification Bits
Port 0 (P01 to P03)*1 3-bit unit internal specification by software POGA.0
Port 1 (P12)*1 Internal specification by software POGA.1
Port 2 (P20 to P23) 4-bit unit internal specification by software POGA.2
Port 3 (P30 to P33) POGA.3
Port 6 (P60 to P63) POGA.6
Port 5 (P50 to P53) Bit-wise internal specificationby mask option*2
* 1. Pull-up resistors cannot be incorporated into the P00 and P10 pins.
2. On the
µ
PD75P402, pull-up resistors cannot be incorporated into port 5.