RSK+RZA1H
5. User Circuitry
R20UT3007EG0200 Rev. 2.00
Page 17 of 53
May 17, 2015
5.5
Port Expander
The RSK+ board utilises two port expander ICs, IC34 and IC35 in order to provide more I/O signals. These
devices are the CAT9554 from On Semiconductor. For further information on these devices visit the On
Semiconductor website at
www.onsemi.com
.
The port expanders provide 8 parallel I/O lines each, which can be accessed via an I
2
C/SMBus serial
connection. On the RSK+ board, they are able to be accessed at different addresses on I
2
C channel 3 on the
MCU. The I
2
C logical address for IC34 is 0x40 and IC35 is 0x41. Table 5.3 details the signal connections to
IC34 and Table 5.4 details the signal connections to IC35.
Port Number
Signal name
Function
0
LED1
LED output control. Output low = ON, output high = OFF
1
LED2
LED output control. Output low = ON, output high = OFF
2
LED3
LED output control. Output low = ON, output high = OFF
3
NOR_A25
Bit #25 of NOR Flash Addressing
4
PMOD1_RST
Reset line for PMOD Channel 1
5
PMOD2_RST
Reset line for PMOD Channel 2
6
SD_CONN_PWR_EN
Power supply enable for external SD card connection
7
SD_MMC_PWR_EN
Power supply enable for MMC card connection
Table 5.3: Port Expander IC34 Connection Details
Port Number
Signal name
Function
0
PX1_EN0
Multiplex control for LCD/DV Data Lines. Low = LCD, High = DV
1
PX1_EN1
Multiplex control for Ethernet/general Data Lines.
Low = general, High = Ethernet.
2
TFT_CS
Chip select for TFT
3
PX1_EN3
Multiplex control for PWM timer channels and audio codec IC14 serial
ADC/DAC I/O lines.
4
USB_OVR_CURRENT
Signal from USB power controller indicating overcurrent condition.
5
USB_PWR_ENA
Enable USB power supply for channel 0
6
USB_PWR_ENB
Enable USB power supply for channel 1
7
PX1_EN7
Multiplex control for Address bus line A18-A21 and sound generator
outputs SGOUT0-4.
Table 5.4: Port Expander IC35 Connection Details
5.6
CAN
There are two CAN channels which connect to the MCU as listed in Table 5.5.
CAN Signal
Function
MCU
Port
Pin
CAN_CTX1
CAN Channel 1 Transmit
P5_10
B7
CAN_CRX1
CAN Channel 1 Receive
P5_9
A7
CAN_CTX2
CAN Channel 2 Transmit
P7_3
J3
CAN_CRX2
CAN Channel 2 Receive
P7_2
H1
Table 5.5: CAN Connection
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