- SS-HQ1 Application Notes -
Ver.1.0.0 January 7, 2005
224
12.2.13.
I/O pin initial settings and preventive measures
CXD3172AR pins S0-S3 (pins 44, 46, 47, and 48) are parameter-controlled I/O pins (Bi-Directional pins). In
external synchronization mode, these pins are used for external synchronization input. However, during
initialization (XRST removed -> parameter application), they are force-set to output mode. Therefore, in order
to prevent short-circuiting during initialization, insert a resistor with approximately 10k ohm resistance.
Fig 12.2-38 Measure to prevent shorting of CXD3172AR I/O pins
If the pins are not being used as input pins (e.g., in INT mode), then they can be left open under the output
mode setting.
Table 12.2-31 CXD3172AR I/O pins and input mode settings
Setting Parameters
Pin Name
Pin No
CAT1_Byte7,8
Initial
value
Input
setting
Remarks
S0 44
S0IN
0 1
S1 46
S1IN
0 1
S2 47
S2SEL
0 7
S3 48
S3SEL
0 7
Controlled by SG
Output under other settings
SG control
S0 (44pin)
S1 (46pin)
S2 (47pin)
S3 (48pin)
External
INput
10k ohm
CXD3172AR