AT91SAM7S256C-MU Atmel, AT91SAM7S256C-MU Datasheet - Page 740

• Manufacturer Part Number: AT91SAM7S256C-MU
• Description: IC ARM7 MCU 32BIT 256K 64-QFN
• Manufacturer: Atmel
• Series: AT91SAMr

Specifications of AT91SAM7S256C-MU

• Core Processor: ARM7
• Core Size: 16/32-Bit
• Speed: 55MHz
• Connectivity: I²C, SPI, SSC, UART/USART, USB
• Peripherals: Brown-out Detect/Reset, DMA, POR, PWM, WDT
• Number Of I /o: 32
• Program Memory Size: 256KB (256K x 8)
• Program Memory Type: FLASH
• Ram Size: 64K x 8
• Voltage - Supply (vcc/vdd): 1.65 V ~ 1.95 V
• Data Converters: A/D 8x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 64-VQFN Exposed Pad, 64-HVQFN, 64-SQFN, 64-DHVQFN
• Processor Series: AT91
• Core: ARM7TDMI
• Data Bus Width: 32 bit
• Data Ram Size: 64 KB
• Interface Type: SPI, TWI, USART, USB
• Maximum Clock Frequency: 55 MHz
• Number Of Programmable I/os: 32
• Number Of Timers: 5
• Operating Supply Voltage: 3.3 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• Minimum Operating Temperature: - 40 C
• Operating Temperature Range: - 40 C to + 85 C
• For Use With: AT91SAM-ICE - EMULATOR FOR AT91 ARM7/ARM9AT91SAM7S-EK - KIT EVAL FOR ARM AT91SAM7S
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -
• Lead Free Status / Rohs Status: Details
• Other names: AT91SAM7S256-MU; AT91SAM7S256-MU

40.21.3.4
40.21.3.5
40.21.4
40.21.4.1
40.21.5
40.21.5.1
40.21.5.2
40.21.5.3
740
AT91SAM7S Series Preliminary
Real Time Timer (RTT)
Serial Peripheral Interface (SPI)
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
SPI: Software Reset Must be Written Twice
20. SPI: Pulse Generation on SPCK
SPI: Bad tx_ready behavior when CSAAT=1 and SCBR = 1
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.
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 corresponding 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.
If a software reset (SWRSTin the SPI Control Register) is performed, the SPI may not work
properly (the clock is enabled before the chip select.
The SPI Control Register field, SWRST needs to be written twice to be set correctly.
In Master Mode, there is an additional pulse generated on SPCK when the SPI is configured as
follows:
None.
If the SPI is programmed with CSAAT = 1, SCBR(baudrate) = 1 and two transfers are performed
consecutively on the same slave with an IDLE state between them, the tx_ready signal does not
rise after the second data has been transferred in the shifter. This can imply for example, that
the second data is sent twice.
Problem Fix/Workaround
Problem Fix/Workaround
Problem Fix/Workaround:
Problem Fix/Workaround
Problem Fix/Workaround
– The Baudrate is odd and different from 1
– The Polarity is set to 1
– The Phase is set to 0
6175K–ATARM–30-Aug-10