Fujitsu MB90460 Series Hardware Manual page 193

CHAPTER 9 I/O PORT
■ Block Diagram of Port 1 Pins
Figure 9.4-1 is a block diagram of port 1 pins.
RDR
Port data register (PDR)
PDR read
PDR write
Port data direction register (DDR)
DDR write
DDR read
When the resource output enable bit is set, the port is forcibly caused to function as resource output pins
regardless of the value in the DDR1 register.
■ Port 1 Registers
Port 1 registers are PDR1, DDR1 and RDR1. The bits making up each register correspond to the port 1
pins on a one-to-one basis. Table 9.4-2 lists the port 1 pins and their corresponding register bits.
Table 9.4-2 Port 1 Pins and their Corresponding Register Bits
Port
PDR1, DDR1, RDR1
Port 1
Corresponding pin
174
Figure 9.4-1 Block Diagram of Port 1 Pins
Output latch
Direction latch
Register bits and corresponding port pins
bit15 bit14
P17 P16
Resource input
Resource output
Resource output enable
Standby control (SPL = 1)
bit13 bit12
P15 P14
Pull-up resistor
About 50k
Pin
bit11 bit10 bit9
P13 P12 P11
bit8
P10