AT91SAM7S256D-AU Atmel, AT91SAM7S256D-AU Datasheet - Page 147

• 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

21.5.1
21.5.2
21.5.3
Communication is performed through the DBGU serial port initialized to 115200 Baud, 8, n, 1.
The Send and Receive File commands use the Xmodem protocol to communicate. Any terminal performing this
protocol can be used to send the application file to the target. The size of the binary file to send depends on the
SRAM size embedded in the product. In all cases, the size of the binary file must be lower than the SRAM size
because the Xmodem protocol requires some SRAM memory to work.
The Xmodem protocol supported is the 128-byte length block. This protocol uses a two-character CRC-16 to guar-
antee detection of a maximum bit error.
Xmodem protocol with CRC is accurate provided both sender and receiver report successful transmission. Each
block of the transfer looks like:
<SOH><blk #><255-blk #><--128 data bytes--><checksum> in which:
Figure 21-4
Figure 21-4. Xmodem Transfer Example
A 48 MHz USB clock is necessary to use the USB Device port. It has been programmed earlier in the device initial-
ization procedure with PLLB configuration.
DBGU Serial Port
Xmodem Protocol
USB Device Port
– <SOH> = 01 hex
– <blk #> = binary number, starts at 01, increments by 1, and wraps 0FFH to 00H (not to 01)
– <255-blk #> = 1’s complement of the blk#.
– <checksum> = 2 bytes CRC16
shows a transmission using this protocol.
Host
SOH 02 FD Data[128] CRC CRC
SOH 01 FE Data[128] CRC CRC
SOH 03 FC Data[100] CRC CRC
ACK
EOT
ACK
ACK
ACK
C
Device
SAM7S Series [DATASHEET]
6175M–ATARM–26-Oct-12
147