NEC PD17062 Datasheet page 205

16.1.3 SIO0MS
The SIO0MS flag specifies the serial interface clock to be used.
When the SIO0MS flag is set to 0, the external clock is selected. When the SIO0MS flag is set to 1, the internal
clock is selected. When the internal clock is selected, its frequency is set by the shift clock frequency register
(RF: 39H).
When the SIO0MS flag is set to 0 in two-wire bus mode, slave operation is specified. When the SIO0MS
flag is set to 1 in two-wire bus mode, master operation is specified.
16.1.4 SIO0TX
If the SIO0TX flag is set to 0 in two-wire bus mode, reception mode is specified. If the SIO0TX flag is set
to 1 in two-wire bus mode, transmission mode is specified.
If the SIO0TX flag becomes 0 upon specifying CH0 serial I/O mode, SI mode (the SDA pin is in input mode)
is specified. If the SIO0TX flag becomes 1 upon specifying CH0 serial I/O mode, SO mode (the SDA pin is in
output mode) is specified.
When the CH1 serial I/O mode is specified, the SIO0TX flag specifies whether the SO pin is to be used as
a serial interface. When the SIO0TX flag is set to 1, the SO pin is used as an SO pin. When the SIO0TX flag
is set to 0, the SO pin is used as a general-purpose port.
SIO0TX
0
1
Table 16-6 SIO0MS Flag Functions
SIO0MS Function
0 Two-wire bus mode : Slave operation
Serial I/O mode
1 Two-wire bus mode : Master operation
Serial I/O mode
Table 16-7 SIO0TX Flag Functions
Two-wire bus mode : RX (reception) mode
CH0 serial I/O mode : SI mode
CH1 serial I/O mode : P0A
Two-wire bus mode : TX (transmission) mode
CH0 serial I/O mode : SO mode
CH1 serial I/O mode : P0A
: External clock operation
: Internal clock operation
Function
is used as a general-purpose port
3
is used as an SO pin
3
PD17062
205