NEC mPD780065 Series Preliminary User's Manual page 247

(c) Busy & strobe control option
Usually, the busy control and strobe control options are simultaneously used as handshake signals. In
this case, the strobe signal is output from the STB/P80 pin, and the BUSY/P81 pin is sampled, and
transmission/reception can be kept waiting while the busy signal is input.
When the strobe control option is not used, the P80/STB pin can be used as a normal I/O port pin.
To use the busy & strobe control option, the following conditions must be satisfied.
• Bit 5 (ATE0) of the serial operating mode register 1 (CSIM1) is set to 1.
• Bit 2 (STRB0) and bit 1 (BUSY10) of the automatic data transmit/receive control register (ADTC0) are
set to 1.
The active level of the busy signal is set by bit 0 (BUSY00) of ADTC0.
BUSY00 = 0: Active high
BUSY00 = 1: Active low
Figure 14-21 shows the operation timing when the busy & strobe control options are used.
When the strobe control option is used, the interrupt request flag (CSIIF1) that is set on completion of
transmission/reception is set after the strobe signal is output.
CHAPTER 14 SERIAL INTERFACE (SIO1)
Preliminary User's Manual U13420EJ2V0UM00
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