AT91SAM7S256D-AU Atmel, AT91SAM7S256D-AU Datasheet - Page 650

• Manufacturer Part Number: AT91SAM7S256D-AU
• Description: ARM Microcontrollers - MCU 256K Flash SRAM 64K ARM based MCU
• Manufacturer: Atmel
• Series: SAM7S256r

Specifications of AT91SAM7S256D-AU

• Rohs: yes
• Core: ARM
• Processor Series: AT91SAM
• Data Bus Width: 16 bit/32 bit
• Maximum Clock Frequency: 55 MHz
• Program Memory Size: 256 KB
• Data Ram Size: 64 KB
• On-chip Adc: Yes
• Operating Supply Voltage: 3 V to 3.6 V
• Operating Temperature Range: - 40 C to + 85 C
• Package / Case: LQFP-64
• Mounting Style: SMD/SMT
• Interface Type: 2-Wire, I2S, SPI, USART
• Length: 7 mm

40.11.7
40.11.7.1
40.11.7.2
40.11.7.3
40.11.7.4
40.11.7.5
40.11.8
40.11.8.1
40.11.8.2
If the Channel Counter Register value is 0 or 1, the Channel Period Register or Channel Duty Cycle Register is
directly modified when writing the Channel Update Register.
Check the Channel Counter Register before writing the update register.
When Channel Period Register equals 0, the period update is not operational.
Do not write 0 in the period register.
In left aligned mode, the first start value of the counter is 0. For the other periods, the counter starts at 1.
None.
Setting Channel Duty Cycle Register (PWM_CDTYx) at 0 in center aligned mode or at 0 or 1 in left aligned mode
may change the polarity of the signal.
Do not set PWM_CDTYx at 0 in center aligned mode.
Do not set PWM_CDTYx at 0 or 1 in left aligned mode.
Erratic behavior of the CHIDx status bit in the PWM_SR Register. When a channel is disabled by writing in the
PWM_DIS Register just after enabling it (before completion of a Clock Period of the clock selected for the channel),
the PWM line is internally disabled but the CHIDx status bit in the PWM_SR stays at 1.
Problem Fix/Workaround
Do not disable a channel before completion of one period of the selected clock.
If an event (RTTINC or ALMS) occurs within the same slow clock cycle during which the RTT_SR is read, the cor-
responding bit might be cleared. This can lead to the loss of this event.
The software must handle the RTT event as an interrupt and should not poll RTT_SR.
Under certain rare circumstances, the Real-time Timer Value (RTT_VR) may be corrupted.
Use RTTINC as an increment for a software counter.
Pulse Width Modulation Controller (PWM)
Real Time Timer (RTT)
Problem Fix/Workaround
Problem Fix/Workaround
Problem Fix/Workaround
Problem Fix/Workaround
Problem Fix/Workaround:
Problem Fix/Workaround
PWM: Update when PWM_CCNTx = 0 or 1
PWM: Update when PWM_CPRDx = 0
PWM: Counter Start Value
PWM: Constraints on Duty Cycle Value
PWM: Behavior of CHIDx Status Bits in the PWM_SR Register
RTT: Possible Event Loss when Reading RTT_SR
RTT: RTT_VR May be Corrupted
SAM7S Series [DATASHEET]
6175M–ATARM–26-Oct-12
650