Datasheet

V850ES/JG3 CHAPTER 17 I
2
C BUS
R01UH0015EJ0300 Rev.3.00 Page 533 of 870
Sep 30, 2010
CHAPTER 17 I
2
C BUS
To use the I
2
C bus function, use the P38/SDA00, P39/SCL00, P40/SDA01, P41/SCL01, P90/SDA02, and
P91/SCL02 pins as the serial transmit/receive data I/O pins (SDA00 to SDA02) and serial clock I/O pins
(SCL00 to SCL02), respectively, and set them to N-ch open-drain output
.
17.1 Mode Switching of I
2
C Bus and Other Serial Interfaces
17.1.1 UARTA2 and I
2
C00 mode switching
In the V850ES/JG3, UARTA2 and I
2
C00 are alternate functions of the same pin and therefore cannot be used
simultaneously. Set I
2
C00 in advance, using the PMC3 and PFC3 registers, before use.
Caution The transmit/receive operation of UARTA2 and I
2
C00 is not guaranteed if these functions are
switched during transmission or reception. Be sure to disable the one that is not used.
Figure 17-1. UARTA2 and I
2
C00 Mode Switch Settings
PMC3
After reset: 0000H R/W Address: FFFFF446H, FFFFF447H
0 0 PMC35 PMC34 PMC33 PMC32 PMC31 PMC30
0 0 0 0 0 0 PMC39 PMC38
89101112131415
PFC3
After reset: 0000H R/W Address: FFFFF466H, FFFFF467H
0 0 0 0 0 0 PFC39 PFC38
0 0 PFC35 PFC34 PFC33 PFC32 PFC31 PFC30
89101112131415
Port I/O mode
UARTA2 mode
I
2
C00 mode
PMC3n
0
1
1
Operation mode
PFC3n
×
0
1
Remarks 1. n = 8, 9
2. × = don’t care