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TMP92CM22
2007-02-16
92CM22-63
3.5.7 Port 9 (P90 to P92)
Port 9 is 3-bit general-purpose I/O port. Each bit can be set individually for input or
output.
In addition to functioning as a general-purpose I/O port, port 9 can also function as a
serial bus interface input (SCK (Clock signal in SIO mode), SO (Data output signal in SIO
mode), SDA (Data signal in I
2
C bus mode), SI (Data input signal in SIO mode) and SCL
(Clock signal in I
2
C bus mode)).
These settings operate by programming to the corresponding bit of P9FC.
Resetting set value of P9CR and P9FC to “0”, all bits are set to input port. And all bits of
output latch are set to “1”.
Figure 3.5.14 Port 9 (P90 to P92)
Internal data bus
Direction control
(on bit basis)
Reset
P9CR write
P9 write
P9 read
P90 (SCK),
P91 (SO/SDA)
P92 (SI/SCL)
Function control
(on bit basis)
P9FC write
SCK output
SO output
SDA output
SCL output
S
Output latch
S
B
Selector
A
S
A
Selector
B
SCK input
SDA input
SI/SCL input
Open-drain enable
P9ODE<P91ODE>
<P92ODE>