Fujitsu MB89950/950A Pager User Manual


 
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CHAPTER 4 I/O PORTS
Operation in stop mode
The output transistors are forcibly turned "OFF" regardless of the PRD0 register value and the pins go to
the high-impedance state if the pin state specification bit in the standby control register (STBC: SPL) is
"1" when the device goes to stop mode. Moreover, to avoid leakage (from floating input pin), input must
be driven by either "1" or "0" when SPL = "1".
Table 4.2-4 "Port 0 pin state" lists the port 0 pin states
Table 4.2-4 Port 0 pin state
Pin name
Normal operation
sleep mode
stop mode (SPL = "0")
Stop mode (SPL = "1") Reset
P00/SEG20 to P07/SEG27
General-purpose I/O ports/segment driver
output
Hi-Z Hi-Z
SPL: Pin state specification bit in the standby control register (STBC)
Hi-Z: High impedance