Texas Instruments Tiva TM4C123GH6PM, User Manual

Page: 10 / 352

Boot Loader
COMMAND_DOWNLOAD
= 0x21
This command is sent to the boot loader to indicate where
to store data and how many bytes will be sent by the
COMMAND_SEND_DATA
commands that follow. The command
consists of two 32-bit values that are both transferred MSB first.
The first 32-bit value is the address to start programming data
into, while the second is the 32-bit size of the data that will be
sent. This command also triggers a mass erase of the flash,
which causes the command to take longer to send the ACK/NAK
in response to the command. This command should be followed
by a
COMMAND_GET_STATUS
to ensure that the program ad-
dress and program size were valid for the microcontroller running
the boot loader.
The format of the command is as follows:
uint8_t pui8Command[9];
pui8Command[0] = COMMAND_DOWNLOAD;
pui8Command[1] = Program Address [31:24];
pui8Command[2] = Program Address [23:16];
pui8Command[3] = Program Address [15:8];
pui8Command[4] = Program Address [7:0];
pui8Command[5] = Program Size [31:24];
pui8Command[6] = Program Size [23:16];
pui8Command[7] = Program Size [15:8];
pui8Command[8] = Program Size [7:0];
COMMAND_RUN
= 0x22
This command is sent to the boot loader to transfer execution
control to the specified address. The command is followed by a
32-bit value, transferred MSB first, that is the address to which
execution control is transferred.
The format of the command is as follows:
uint8_t pui8Command[5];
pui8Command[0] = COMMAND_RUN;
pui8Command[1] = Run Address [31:24];
pui8Command[2] = Run Address [23:16];
pui8Command[3] = Run Address [15:8];
pui8Command[4] = Run Address [7:0];
10 April 8, 2013