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stm32:desig: Add DFU compatible serial generation 

Reviewed-by: Karl Palsson <karlp@tweak.net.au>
Modified to provide better doxygen and consistent api names.
This commit is contained in:
Dave Hylands 2016-11-27 12:29:02 -08:00 committed by Karl Palsson
parent 5bf61c537f
commit 755ce402e2
2 changed files with 42 additions and 1 deletions
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10
include/libopencm3/stm32/desig.h
View File

@ -47,11 +47,19 @@ void desig_get_unique_id(uint32_t *result);
* Read the full 96 bit unique identifier and return it as a
* zero-terminated string
* @param string memory region to write the result to
8 @param string_len the size of string in bytes
* @param string_len the size of string in bytes
*/
void desig_get_unique_id_as_string(char *string,
unsigned int string_len);
/**
* Returns the same serial number that the factory DFU
* bootloader reports (via USB descriptors).
* @param string memory region to write the result to. This is
* expected to be a 13-byte buffer.
*/
void desig_get_unique_id_as_dfu(char *string);
END_DECLS
#endif

33
lib/stm32/desig.c
View File

@ -53,3 +53,36 @@ void desig_get_unique_id_as_string(char *string,
string[len] = '\0';
}
/**
* Generate a serial number from the unique id registers as the DFU bootloader.
* This document: http://www.usb.org/developers/docs/devclass_docs/usbmassbulk_10.pdf
* says that the serial number has to be at least 12 digits long and that
* the last 12 digits need to be unique. It also stipulates that the valid
* character set is that of upper-case hexadecimal digits.
* The onboard DFU bootloader produces a 12-digit serial based on the
* 96-bit unique ID. Show the serial with ```dfu-util -l``` while the
* MCU is in DFU mode.
* @see https://my.st.com/52d187b7 for the algorithim used.
* @param string pointer to store serial in, must be at least 13 bytes
*/
void desig_get_unique_id_as_dfu(char *string) {
uint8_t *id = (uint8_t *)DESIG_UNIQUE_ID_BASE;
uint8_t serial[6];
serial[0] = id[11];
serial[1] = id[10] + id[2];
serial[2] = id[9];
serial[3] = id[8] + id[0];
serial[4] = id[7];
serial[5] = id[6];
uint8_t *ser = &serial[0];
uint8_t *end = &serial[6];
const char hex_digit[] = "0123456789ABCDEF";
for (; ser < end; ser++) {
*string++ = hex_digit[(*ser >> 4) & 0x0f];
*string++ = hex_digit[(*ser >> 0) & 0x0f];
}
*string = '\0';
}