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4.3 Serial Bus
Pin Name
default
D/I/O
mode
Normal mode
J1.11 TO_0 D/I
I/O_10
Timer
output
channel_0
J1.12 TO_1 D/I
I/O_1
Timer
output
channel_1
J1.13 TI_0 D/I
I/O_11
Timer input channel_0
J1.14 TI_1 D/I
I/O_0
Timer input channel_1
J1.15 SCL
K
D/O I/O_26 UZI,
don’t
change to this mode
J1.16 DIO9 D/I
I/O_9
A19,
don’t change to this mode
J1.17 DIO4 D/I
I/O_4
DT/R, don’t change to this mode
J1.18 DIO1
4
D/I I/O_14 MCS0,
don’t
change to this mode
Every pin can be configured by mode control register & direction control
register as follows:
Mode control
register=0xff70
Direction control
register=0xff72
Programmable Function
0 0 Normal
mode
0 1 D/I
with
pull-up/pull-down
resistor(10K)
1 0 D/O
1
1
D/I without pull-up/pull-down
register(10K)
After the I/O pins are configured, user can read /write to
data register, 0xff74
,
to access these I/O pins. Refer to Sec. 4.3.1 or Sec. 4.3.2 for demo program.
4.3.1 Using the SCLK
The 7188 series uses this signal as a CLOCK source to drive all on-board
serial devices, so it always should be programmed as D/O. Changing this signal
to other configurations will cause serious errors. User can use this signal to
drive external serial devices without any side effects. The software driver
provides two subroutines to set SCLK high or low as follows:
ClockLow(); /* SCLK=0=Low
*/
ClockHigh();
/* SCLK=1=High */
7188E Series Hardware User’s Manual, 2004, v2.2, 7MH-016-22 ----- 49