sx1441 Semtech Corporation, sx1441 Datasheet - Page 36

• Manufacturer Part Number: sx1441
• Description: Bluetooth V1.2 Soc For Voice And Data Applications With Dsp Capabilities
• Manufacturer: Semtech Corporation

Personal Area Network
3.9.3 Multiplexing PB With Other Peripherals
Port PB acts as a GPIO port by default. This functionality can be overridden as other functions are enabled as
shown in Table 58.
When the counters are used to implement a PWM function (see 3.10), the PB[0] and PB[1] terminals are used as
outputs (PB[0] is used if bit 0 in RegCntConfig1 is set to 1, PB[1] is used if bit 1 in RegCntConfig1 is set to 1) and
the PWM generated values override the values written in RegPBout. However, RegPBDir[0] and RegPBDir[1]
are not automatically overwritten and have to be set to 1.
If bit 1 is set in RegSysMisc, the ck32kHz low prescaler output is output on PB[3]. This overrides the value
contained in RegPBOut[3]. However, RegPBDir[3] must be set to 1. The frequency and duty cycle of the clock
signal are given in Figure 16.
Similarly, If bit 0 is set in RegSysMisc, the CPU clock is output on PB[2] as described on Figure 17. This overrides
the value contained in RegPBOut[2]. However, RegPBDir[2] must be set to 1.
© Semtech 2006
Pos
7:0
Pos
7:0
Pos
7:0
Port PB number
7
6
5
4
3
2
1
0
RegPBDir
PBDir
RegPBOpen
PBOpen
RegPBPullup
PBPullup
Priority
Medium
UA_RX
UA_TX
UA_RTS
UA_CTS
ck32k
CPU clock
counter C (C+D) PWM1
counter A (A+B) PWM0
rw
1/f
r/w
rw
r/w
rw
r/w
ckRCext
Figure 16 - ck32k output clock timing
Table 56 - RegPBOpen register
Reset
00000000
Reset
00000000
Reset
11111111
1/f
Table 55 - RegPBDir register
Table 58 - PB[7:0] usage
Table 57 - RegPBPullup
ck32kHz
36
Function
for each corresponding PB pad:
1 = pad is configured as digital output
0 = pad is configured as digital input
Function
for each corresponding PB pad:
1 = pad is configured as open drain
0 = pad is configured as push-pull
Function
for each corresponding PB pad:
1 = pull-up enabled
0 = pull-up disabled
Low
GPIO
GPIO
GPIO
GPIO
GPIO
GPIO
GPIO
GPIO
SX1441 – Bluetooth® 1.2 SoC
www.semtech.com
Data Sheet