Pins Used For Ethernet Boot - Texas Instruments TMS320C6A816 Series Technical Reference Manual

Peripheral Booting
21.8.4.2 BOOTP (RFC 951)
The device then proceeds to obtain the IP and Boot information using BOOTP protocol. The device
prepares and broadcasts the BOOTP message that has the following information:
• Device MAC address in "chaddr" field – to uniquely identify the device to the server.
• "Vender-class-identifier" option number 60 (RFC 1497, RFC 1533). Servers could use this
information to identify the device type. The value present is "DM816x ROM v1.0"
• "Client-identifier" option number 61 (RFC 1497, RFC 1533). This has the ASIC-ID structure which
contains additional info for the device.
The device then expects a BOOTP response that provides the following information for the booting to
proceed:
• Device IP address from "yiaddr" field
• Subnetmask from extended option 1 (RFC 1497, RFC 1533)
• Gateway IP from extended option number 3 (RFC 1497, RFC 1533) or from "giaddr" field of BOOTP
response.
• Boot image filename from "file" field
Timeouts and retries
• Exponentially increasing timeouts starting from 4s
• Five retries
21.8.4.3 FTP (RFC 1350)
After a successful BOOTP completion, the device initiates the TFTP download of the boot image into
SRAM. The device has the capability to reach TFTP server within the local subnet or outside, though
the gateway.
Timeouts and retries
• Timeout of 1s to receive a response for the READ request
• 5 retries for the READ request
• Retries are managed by server once data transfer starts (server re-sends a data packet if the ACK
was not received within a timeout value)
• Device has a 60s timeout to complete the data transfer, to handle the scenario if the server dies in
the middle of a data transfer
21.8.4.4 Pins Used
The list of pins that are configured by the ROM in case of Ethernet boot mode are in
that all the pins might not be driven at boot time.
Signal name
col
crs
gtx_clk
rx_clk
rxd0-rxd7
rxdv
rxer
tx_clk
txd_0-txd7
txen
mclk
mdio
2022
ROM Code Memory and Peripheral Booting
Preliminary
Table 21-22. Pins Used for Ethernet Boot
Pin used
gmii0_col
gmii0_crs
gmii0_gtxclk
gmii0_rxclk
gmii0_rxd0-rxd7
gmii0_rxdv
gmii0_rxer
gmii0_txclk
gmii0_txd0-txd7
gmii0_txen
gmii0_mclk
gmii0_mdio
© 2011, Texas Instruments Incorporated
www.ti.com
Table 21-22. Note
SPRUGX9 – 15 April 2011
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