PIC18F2550 equipped with a USB bootloader : UBW (USB Bit Whacker)
UBW(USB Bit Whacker) を用いた実験を行う為に、秋月電子通商 AE-18F2550 マイコンボードに準じて、PIC18F2550 に bootloader を実装した実験用ボードを作製した。
(Revision on June 9, 2017)
<< Clock of my USB board >>
A configuration of CONFIG1L register of a USB bootloader is set to “Divide by 5 (20 MHz oscillator input) and 96 MHz PLL divided by 2 to derive system clock”, so Fosc is 48MHz derived from a primary oscillator using a 20MHz ceramic resonator.
<< Pin connection of my USB board >>
Bootloader ( RC0 – LED, RC1 – LED, RC2 – switch2 (pull down), MCLR – switch1 (pull down) )
LCD : SC1602BBWB-XA-GB-G ( RS – RB2, R/W – GND, E – RB3, Data bus – RB4～RB7 )
<< Three components of the UBW bootloader >>
1) UBW firmware.hex into a PIC18F2550 (external-resonator of 20MHz, CPU-clock of 48MHz, code-offset of 0x800);
2) USB driver into a Windows PC;
3) Myboot into a Windows PC (code-offset of 0x800);
<< LCD display code >>
(A code for a USB bootloader must be compiled by XC8 at the code offset, 0x800.)
UBW対応設定：
MPLAB X IDEのメニューから、[File] –> [Project Propaties]を選択
XC8 linker を選択
Option categoried欄で、Additional options を選択
Codeoffset欄に、「0x800」を入力