現在我們已經知道 ID EEPROM 的資料格式和內容，那麼如何產生 .epp 檔案呢？想當然耳得用 eepmake 的了。不過它的唯一說明是︰

pi@raspberrypi:~/hats/eepromutils 

 

，這樣該怎麼用勒！也許有時曉得程式的用法之途徑，就是閱讀其『原始碼』以及各種『相關檔』文本。然後順著『麵包屑』走︰

/*

* Parses EEPROM text file and createds binary .eep file

* Usage: eepmake input_file output_file

*/

#include <stdio.h>

#include <stdlib.h>

#include <ctype.h>

#include <string.h>

#include <stdbool.h>

#include <fcntl.h>

#include “eeptypes.h“

#define HEADER_SIGN 0x69502d52 //”R-Pi” in ASCII reversed for endianness

………

 

如是自會發現︰

########################################################################

# EEPROM settings text file

#

# Edit this file for your particular board and run through eepmake tool,

# then use eepflash tool to write to attached HAT ID EEPROM

#

# Tools available:

# eepmake Parses EEPROM text file and creates binary .eep file

# eepdump Dumps a binary .eep file as human readable text (for debug)

# eepflash Write or read .eep binary image to/from HAT EEPROM

#

########################################################################

########################################################################

# Vendor info

# 128 bit UUID. If left at zero eepmake tool will auto-generate

# RFC 4122 compliant UUID

product_uuid 00000000-0000-0000-0000-000000000000

# 16 bit product id

product_id 0x0000

# 16 bit product version

product_ver 0x0000

# ASCII vendor string (max 255 characters)

vendor “ACME Technology Company”

# ASCII product string (max 255 characters)

product “Special Sensor Board”

########################################################################

# GPIO bank settings, set to nonzero to change from the default.

# NOTE these setting can only be set per BANK, uncommenting any of

# these will force the bank to use the custom setting.

# drive strength, 0=default, 1-8=2,4,6,8,10,12,14,16mA, 9-15=reserved

gpio_drive 0

# 0=default, 1=slew rate limiting, 2=no slew limiting, 3=reserved

gpio_slew 0

# 0=default, 1=hysteresis disabled, 2=hysteresis enabled, 3=reserved

gpio_hysteresis 0

# If board back-powers Pi via 5V GPIO header pins:

# 0 = board does not back-power

# 1 = board back-powers and can supply the Pi with a minimum of 1.3A

# 2 = board back-powers and can supply the Pi with a minimum of 2A

# 3 = reserved

# If back_power=2 then USB high current mode will be automatically

# enabled on the Pi

back_power 0

########################################################################

# GPIO pins, uncomment for GPIOs used on board

# Options for FUNCTION: INPUT, OUTPUT, ALT0-ALT5

# Options for PULL: DEFAULT, UP, DOWN, NONE

# NB GPIO0 and GPIO1 are reserved for ID EEPROM so cannot be set

# GPIO FUNCTION PULL

# —- ——– —-

#setgpio 2 INPUT DEFAULT

#setgpio 3 INPUT DEFAULT

#setgpio 4 INPUT DEFAULT

#setgpio 5 INPUT DEFAULT

#setgpio 6 INPUT DEFAULT

#setgpio 7 INPUT DEFAULT

#setgpio 8 INPUT DEFAULT

#setgpio 9 INPUT DEFAULT

#setgpio 10 INPUT DEFAULT

#setgpio 11 INPUT DEFAULT

#setgpio 12 INPUT DEFAULT

#setgpio 13 INPUT DEFAULT

#setgpio 14 INPUT DEFAULT

#setgpio 15 INPUT DEFAULT

#setgpio 16 INPUT DEFAULT

#setgpio 17 INPUT DEFAULT

#setgpio 18 INPUT DEFAULT

#setgpio 19 INPUT DEFAULT

#setgpio 20 INPUT DEFAULT

#setgpio 21 INPUT DEFAULT

#setgpio 22 INPUT DEFAULT

#setgpio 23 INPUT DEFAULT

#setgpio 24 INPUT DEFAULT

#setgpio 25 INPUT DEFAULT

#setgpio 26 INPUT DEFAULT

#setgpio 27 INPUT DEFAULT

 

eepmake input_file 格式的哩。

從『原始碼』也可以證實 128 bit UUID 不需要給， eepmake 會自動產生︰

	/* Vendor info related part */
# line 198

if (strcmp(cmd, "product_uuid")==0) {
        product_serial_set = true; //required field
        high1 = 0; high2 = 0;

        sscanf(c, "%100s %08x-%04x-%04x-%04x-%04x%08x\n", cmd, &vinf->serial_4,
&high1, &vinf->serial_3, &high2, &vinf->serial_2, &vinf->serial_1);

        vinf->serial_3 |= high1<<16;
        vinf->serial_2 |= high2<<16;

        if ((vinf->serial_4==0) && (vinf->serial_3==0) && (vinf->serial_2==0) && (vinf->serial_1==0)) {
                //read 128 random bits from /dev/urandom
                int random_file = open("/dev/urandom", O_RDONLY);
                ssize_t result = read(random_file, &vinf->serial_1, 16);
                close(random_file);
                if (result <= 0) printf("Unable to read from /dev/urandom to set up UUID");
                else {
                        //put in the version
                        vinf->serial_3 = (vinf->serial_3 & 0xffff0fff) | 0x00004000;

                        //put in the variant
                        vinf->serial_2 = (vinf->serial_2 & 0x3fffffff) | 0x80000000;
                        printf("UUID=%08x-%04x-%04x-%04x-%04x%08x\n", vinf->serial_4, vinf->serial_3>>16, vinf->serial_3 & 0xffff, vinf->serial_2>>16, vinf->serial_2 & 0xffff, vinf->serial_1);
                }
        }

 

因此剩下的事就是好好了解 40W GPIOs 怎麼設定的也☆