Pin descriptions – Oki BISM2 User Manual
Page 4
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3.2
Pin Descriptions
The Hirose DF12C board-to-board connector on the module is a 40-pin double-row receptacle.
The table below defines the pin functions. Note that this pin-out is as viewed from the underside of
the Module.
Pin
No.
Signal
Description
Pin
No.
Signal
Description
1
Analogue 0
1.8v Max
2
GPIO1
I/O for Host.
3
Analogue 1
1.8v Max
4
GPIO2
I/O for Host
5
SPI_MISO
SPI bus serial O/P
6
UART_RI
‘Ring’ Input or Output
7
SPI_CSB
SPI bus chip select I/P
8
UART_DCD
Input or Output
9
SPI_CLK
SPI bus clock I/P
10
UART_DSR
Input
11
GND
12
GPIO3/UART_DTR I/O for Host
13
RESET
Reset I/P *
14
GPIO4
I/O for Host & LED
15
GND
16
GPIO5
I/O for Host
17
SPI_MOSI
SPI bus serial I/P
18
GND
19
UART_CTS
Clear to Send I/P
20
PCM_CLK
PCM Clock I/P
21
UART_TX
Transmit Data O/P
22
PCM_IN
PCM Data I/P
23
UART_RTS
Request to Send O/P
24
PCM_SYNC
PCM Sync I/P
25
UART_RX
Receive Data I/P
26
PCM_OUT
PCM Data O/P
27
VCC_3V3
3.3V Monitor
28
N/C
29
VCC_5V
3.6V < VIN < 7.0V
30
GND
31
N/C
32
USB / RESERVED
Do not connect
33
GPIO6 **
I/O for Host
34
USB / RESERVED
Do not connect
35
GPIO7 **
I/O for Host
36
GND
37
GPIO8 **
I/O for Host
38
GND
39
GPIO9
I/O for Host
40
N/C
Notes:
* The reset circuitry within the BISM Serial Modules now incorporates a brown-out detector within
the module. Customers migrating from previous modules should check their implementation, as they
may be able to simplify their external power supply design. The reset line has a fixed 10kOhm pull
down resistor to ground.
** Pins 33, 35 and 37 were N/C on BISM1. Pin 39 was a 1V8 monitor. Designers migrating between
designs should be aware that these are now available as I/O. Default configuration is as an input
PIO lines can be configured through software to be either inputs or outputs with weak or strong pull-
ups or pull-downs. At reset, all PIO lines are configured as inputs with weak pull-downs.
UART_RX, UART_TX, UART_CTS, UART_RTS, UART_RI, UART_DCD and UART_DSR are all 3.3v level
logic. For example, when RX and TX are idle they will be sitting at 3.3V. Conversely for handshaking
pins CTS, RTS, RI, DCD, DSR a 0v is treated as an assertion.
Pin 6 (UART_RI) is active low. It is normally 3.3v. When a remote device initiates a connection, this
pin goes low. This means that when this pin is converted to RS232 voltage levels it will have the
correct voltage level for assertion.