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“Bootloader on nRF” Mark
alternative to optical bootloader
safer and easier to SCuM
application is complete
PC-to-NRF over UART, based on Teensy code
“prepare“ command
64kB of data
“transmit“ command
typically
SCuM behavior: always load 64 kB
not tested on SCuM, but using LEDs
UART without
on the computer side, Python script
4 stages
loading from nRF to SCuM
Mark describes the 3 wire pin
DATA pin: bit value at each
LATCH pin: high every 32th operation, toggles every 4B
CLK pin: toggle when SCuM should read bits. Max speed of CLK pin is 1MHz per David Burnett
triggering of the bootloading
system boots up with no boot source
3-wire bus is constantly listening for bits
when 3-wire bootload is done, inside SCuM, issues soft resets
2 reset pins: soft reset (resets PC), hard pin (clears RAM and all)
next steps
code review with Thomas Watteyne
CRC
document
push to GitHub
suggestions from David Burnett
verify voltage levels
additional function for ADC
calibration routines for ADC
analog scan chain function
discussion about voltage levels
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