User's Manual

CRXi

µµ

Core Module

µµ

X Logic,

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Note the prompt 0>. The 0 indicates we are on the default page 0. At this prompt the command set of the

bootloader can be run. To see the available commands at any time, type ‘?’. A review of commands will

follow.

Figure 5

All commands are single characters. Some commands take parameters and these are shown in the text to

the right of the character. For example, the W (Write) command takes 3 parameters. The first is the value

you want to write. The second and third are the start address and end address. Typing “W FC 0000 01FF”

would fill data space (NVSRAM in this case) with the value 0FCh (252 decimal) into consecutive locations

beginning at address 0000h end ending at 01FFh. Any valid data space can be written to – including chip

selects and configuration registers (CSIOP).

Note that jumper J3 must be in place for the bootloader to execute. After a reset, if no jumper is seen on J3,

user code at address 0000h will execute. If jumper is present, the bootloader will poll the serial port for

approximately 5 seconds. If a keypress is detected within this time, the bootloader will start. If the timeout

occurs, bootloader is exited and user code is executed at address 0000h. Users developing custom serial

interface software can use the bootup transmission character to determine if the CRXi has been reset. When

the CRXi powers up or is reset, the bootloader transmits a single tilde (~) char out its serial port before

beginning the polling sequence. Users software could read this character and perform some action. One

possibility is upon receiving the tilde character, writing out any character will be received by the CRXi and

keep the part in bootloader mode.

Bootloader Command Set

Detailed review of bootloader commands.

Displays help page. See Figure 5.