AT91SAM7XC256 Datasheet, PDF (137/675 Pages) ATMEL Corporation – Thumb-based Microcontrollers

AT91SAM7XC256/128 Preliminary
Table 22-2. Handled Standard Requests (Continued)
Request
Definition
GET_STATUS
Returns status for the specified recipient.
SET_FEATURE
Used to set or enable a specific feature.
CLEAR_FEATURE
Used to clear or disable a specific feature.
The device also handles some class requests defined in the CDC class.
Table 22-3. Handled Class Requests
Request
Definition
SET_LINE_CODING
Configures DTE rate, stop bits, parity and number of
character bits.
GET_LINE_CODING
Requests current DTE rate, stop bits, parity and number
of character bits.
SET_CONTROL_LINE_STATE
RS-232 signal used to tell the DCE device the DTE
device is now present.
Unhandled requests are STALLed.
22.4.3.2
Communication Endpoints
There are two communication endpoints and endpoint 0 is used for the enumeration process.
Endpoint 1 is a 64-byte Bulk OUT endpoint and endpoint 2 is a 64-byte Bulk IN endpoint.
SAM-BA Boot commands are sent by the host through the endpoint 1. If required, the mes-
sage is split by the host into several data payloads by the host driver.
If the command requires a response, the host can send IN transactions to pick up the
response.
22.5
Hardware and Software Constraints
• SAM-BA boot copies itself in the SRAM and uses a block of internal SRAM for variables
and stacks. The remaining available size for the user code is 57344 bytes for
AT91SAM7XC256 and 24576 bytes for AT91SAM7XC128.
• USB requirements:
– 18.432 MHz Quartz
Table 22-4. User Area Addresses
Device
Start Address
AT91SAM7XC256
0x202000
AT91SAM7XC128
0x202000
End Address
0x210000
0x208000
Size (bytes)
57344
24576
Table 22-5.
Peripheral
DBGU
DBGU
Pins Driven during Boot Program Execution
Pin
DRXD
DTXD
PIO Line
PA27
PA28
6209B–ATARM–10-Feb-06
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