M16C/62P Group (M16C/62P, M16C/62PT)
17. Serial Interface
Rev.2.41
Jan 10, 2006
Page 225 of 390
REJ09B0185-0241
Figure 17.35
SIM Interface Connection
17.1.6.1
Parity Error Signal Output
The parity error signal is enabled by setting the U2ERE bit in the U2C1 register to “1”.
The parity error signal is output when a parity error is detected while receiving data. This is achieved by pulling
the TXD2 output low with the timing shown in Figure 17.36. If the R2RB register is read while outputting a
parity error signal, the PER bit is cleared to “0” and at the same time the TXD2 output is returned high.
When transmitting, a transmission-finished interrupt request is generated at the falling edge of the transfer clock
pulse that immediately follows the stop bit. Therefore, whether a parity signal has been returned can be
determined by reading the port that shares the RXD2 pin in a transmission-finished interrupt routine.
Figure 17.36
Parity Error Signal Output Timing
Microcomputer
SIM card
TXD2
RXD2
ST : Start bit
P : Even Parity
SP : Stop bit
D0
D1
D2
D3
D4
D5
D6
D7
P
SP
ST
(NOTE 1)
Transfer
clock
RXD2
TXD2
“H”
“L”
“H”
“L”
“H”
“L”
“1”
“0”
This timing diagram applies to the case where the direct format is
implemented.
NOTES :
1. The output of microcomputer is in the high-impedance state
(pulled up externally).
IR bit in U2C1
register
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