SAM7S256_14 Datasheet, PDF (724/775 Pages) ATMEL Corporation – ARM-based Flash MCU

CTS must not go low during a time slot occurring between 2 Master Clock periods before the starting bit and 16
Master Clock periods after the rising edge of the starting bit.
40.21.10.3 USART: Hardware Handshaking – Two Characters Sent
If CTS switches from 0 to 1 during the TX of a character and if the holding register (US_THR) is not empty, the con-
tent of US_THR will also be transmitted.
Problem Fix/Workaround
Don't use the PDC in transmit mode and do not fill US_THR before TXEMPTY is set at 1.
40.21.10.4 USART: XOFF Character Bad Behavior
The XOFF character is sent only when the receive buffer is detected full. While the XOFF is being sent, the remote
transmitter is still transmitting. As only one Holding register is available in the receiver, characters will be lost in
reception. This makes the software handshaking functionality ineffective.
Problem Fix/Workaround
None.
40.21.10.5 USART: DCD is active High instead of Low
The DCD signal is active at High level in the USART Modem Mode.
DCD should be active at Low level.
Problem Fix/Workaround
Add an inverter.
40.21.11 Voltage Regulator
40.21.11.1 Voltage Regulator: Current Consumption in Deep Mode
Current consumption in Deep Mode is maximum 60 µA instead of 25 µA.
Due to current rejection from VDDIN to VDDCORE, the current consumption in Deep Mode cannot be guaranteed.
Instead, 60 µA is guaranteed whatever the condition.
Problem Fix/Workaround
None.
40.21.11.2 Voltage Regulator: Load Versus Temperature
Maximum load is 50 mA at 85 °C (instead of 100 mA).
Maximum load is 100 mA at 70°C.
Problem Fix/Workaround
None.
SAM7S Series [DATASHEET]
6175M–ATARM–26-Oct-12
724