Data Sheet

Bluegiga Technologies Oy
Page 33 of 52
6.6.4 UART 4
Pin#
UART 4
Other functions
Net name
61
Receive
DUART RX, AUART 0 CTS
AUART0_CTS
62
Transmit
DUART TX, AUART 0 RTS
AUART0_RTS
83
Clear-to-send
SAIF0_MCLK, PWM 3
SAIF0_MCLK
85
Transmit
SAIF0_SDATA0, PWM 6
SAIF0_SDATA0
86
Receive
SAIF0_BITCLK, PWM 5
SAIF0_BITCLK
87
Request-to-send
SAIF0_LRCLK, PWM 4
SAIF0_LRCLK
Table 41: UART 4
The fourth UART is not available by default, but can be configured to be available from two different locations.
Using UART 4 disables either CPU Audio or UART 0’s hardware flow-control lines.
If hardware flow control is required, then the CPU Audio pins (83-87) can be configured to provide the UART 4
functionality instead of CPU Audio. Using UART 4 with hardware flow control at the same time as CPU Audio
is not possible.
If hardware flow control is not required for UART 4 or for UART 0, then the hardware flow control lines of
UART 0 can be configured to provide UART 4 RX/TX instead.
6.6.5 Debug UART
Pin#
Debug UART
Alternative functions
UART I/O direction
Net name
148
Receive
I2C1 SDA, PWM0
Input to module
PWM0
149
Transmit
I2C1 SCL, PWM1
Output from module
PWM1
59
Request-to-send
UART 0 TX
Output from module
AUART0_TX
60
Clear-to-Send
UART 0 RX
Input to module
AUART0_RX
61
Receive
UART 0 CTS, UART 4 RX
Input to module
AUART0_CTS
62
Transmit
UART 0 RTS, UART 4 TX
Output from module
AUART0_RTS
Table 42: DEBUG UART
By default the Debug UART is provided on pins 148 and 149 without using hardware flow control. This will
prevent the use of the second I
2
C port. Alternatively the Debug UART can be configured to be available from
the pins of UART 0 as seen in the table above.
The main difference between the Debug UART and the Application UARTs is that there is no DMA for the
Debug UART and the maximum baud rate is 115.2Kb/s. It unsuitable for any high throughput use-cases and
consumes more processor resources than the other UART interfaces, making it best suited for debugging. In