BCM20730 Data Sheet
GPIO Port
Table 6: XTAL Oscillator Characteristics
Parameter
Symbol
Conditions
Minimum
Typical
Maximum
Unit
Output
frequency
F
–
–
32.768
–
kHz
oscout
Frequency
tolerance
–
Crystal dependent –
100
–
ppm
Start-up time
XTAL drive level P
T
–
–
0.5
–
–
500
–
ms
μW
startup
For crystal
selection
drv
XTAL series
resistance
XTAL shunt
capacitance
R
For crystal
selection
For crystal
selection
–
–
–
–
70
kΩ
series
C
1.3
pF
shunt
GPIO Port
The BCM20730 has 14 general-purpose I/Os (GPIOs) in the 32-pin package, 22 GPIOs in the 40-pin package, and
40 GPIOs in the 64-pin package. All GPIOs support programmable pull-up and pull-down resistors, and all
support a 2 mA drive strength except P26, P27, P28, and P29, which provide a 16 mA drive strength at 3.3V
supply.
Port 0–Port 1, Port 8–Port 23, and Port 28–Port 38
All of these pins can be programmed as ADC inputs.
Port 26–Port 29
P[26:29] consists of four pins. All pins are capable of sinking up to 16 mA for LED. These pins also have the PWM
function, which can be used for LED dimming.
PWM
The BCM20730 has four internal PWM channels. The PWM module consists of the following:
• PWM1–4
• Each of the four PWM channels, PWM1–4, contains the following registers:
– 10-bit initial value register (read/write)
– 10-bit toggle register (read/write)
– 10-bit PWM counter value register (read)
BROADCOM
®
September 9, 2013 • 20730-DS108-R
Page 27
BROADCOM CONFIDENTIAL
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