BCM43907 Preliminary Data Sheet
PWM
Table 6 shows the JTAG_SEL and TAP_SEL states for test and debug function selection. Test and debug
function selection is independent of the debugging interface (JTAG or SWD) being used.
Table 6: JTAG_SEL and TAP_SEL States for Test and Debug Function Selection
JTAG_SEL State TAP_SEL State
Test and Debug Function
0
0
1
1
0
1
0
1
JTAG not used.
JTAG not used.
Access the LV tap directly for ATE and bring-up.
Access either of the ARM Cortex-R4’s directly via either the 5-pin JTAG
port or the 2-pin SWD configuration.
PWM
The BCM43907 provides up to six independent pulse width modulation (PWM) channels. The following features
apply to the PWM channels:
•
•
•
Each channel is a square wave generator with a programmable duty cycle.
Each channel generates its duty cycle by dividing down the input clock.
Both the high and low duration of the duty cycle can be divided down independently by a 16-bit divider
register.
•
•
•
•
Each channel can work independently or update simultaneously.
Pairs of PWM outputs can be inverted for devices that need a differential output.
Continuous or single pulses can be generated.
The input clock can either be a high-speed clock from a PLL channel or a lower speed clock at the crystal
frequency.
Real-Time Clock
The BCM43907 provides a real-time clock (RTC) provided that an accurate 32.768 kHz crystal is used. The RTC
generates date/time using the 32.768 kHz reference and is always powered on when the chip is on, except while
in Hibernation mode.
The RTC has a precision of seconds and will display the calendar day and time provided the initial start time is
programmed correctly. The second, minute, hour, day, month, year, and 24-hour mode can be set individually.
Interrupts can be set on any periodic time event or on specific time events. The PMU uses the RTC interrupt to
determine when to wake up the chip.
Broadcom®
March 12, 2016 • 43907-DS104-R
Page 33
BROADCOM CONFIDENTIAL
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