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474
16.2.7
Serial/Timer Control Register (STCR)
Bit
Initial value
Read/Write
7
—
0
R/W
6
IICX1
0
R/W
5
IICX0
0
R/W
4
IICE
0
R/W
3
FLSHE
0
R/W
0
ICKS0
0
R/W
2
—
0
R/W
1
ICKS1
0
R/W
STCR is an 8-bit readable/writable register that controls register access, the I
2C interface
operating mode (when the on-chip IIC option is included), and on-chip flash memory (F-ZTAT
versions), and selects the TCNT input clock source. For details of functions not related to the I
2C
bus interface, see section 3.2.4, Serial/Timer Control Register (STCR), and the descriptions of
the relevant modules. If a module controlled by STCR is not used, do not write 1 to the
corresponding bit.
STCR is initialized to H'00 by a reset and in hardware standby mode.
Bit 7—Reserved: Do not write 1 to this bit.
Bit 6—I
2C Transfer Select 1 (IICX1): This bit, together with bits CKS2 to CKS0 in ICMR of
IIC1, selects the transfer rate in master mode. For details, see section 16.2.4, I
2C Bus Mode
Register (ICMR).
Bit 5—I
2C Transfer Select 0 (IICX0): This bit, together with bits CKS2 to CKS0 in ICMR of
IIC0, selects the transfer rate in master mode. For details, see section 16.2.4, I
2C Bus Mode
Register (ICMR).
Bit 4—I
2C Master Enable (IICE): Controls CPU access to the I2C bus interface data and
control registers (ICCR, ICSR, ICDR/SARX, ICMR/SAR).
Bit 4
IICE
Description
0
CPU access to I
2C bus interface data and control registers is disabled (Initial value)
1
CPU access to I
2C bus interface data and control registers is enabled
Bit 3—Flash Memory Control Register Enable (FLSHE): Controls the operation of the flash
memory in F-ZTAT versions. For details, see section 22, ROM.
Bit 2—Reserved: Do not write 1 to this bit.
Bits 1 and 0—Internal Clock Source Select 1 and 0 (ICKS1, ICSK0): These bits, together
with bits CKS2 to CKS0 in TCR, select the clock input to the timer counters (TCNT). For
details, see section 12.2.4, Timer Control Register (TCR).