F281x board setting

TMS320F281x checks below four pins at the reset to decide the booting mode.

GPIOF4(SCITXDA)	GPIOF12(MDXA)	GPIOF3(SPISTEA)	GPIOF2(SPICLK)	Boot mode
1	x	x	x	FLASH(0x3F7FF6)
0	1	x	x	SPI boot
0	0	1	1	SCI boot (SCI-A) (RAM boot)
0	0	1	0	H0 SARAM(0x3F8000)
0	0	0	1	OTP (0x3D7800)

easyDSP uses two kinds boot mode. 'SCI' for RAM booting, 'Flash' for flashrom booting (yellow part in above table). Therefore, fix GPIOF2, GPIOF3 and GPIOF12 to '1', '1' and '0' respectively. And connect GPIOF4(SCITXDA) to /BOOT pin of easyDSP, as shown in below connection.

- power pin (#4) of easyDSP 5x2 header should be connected to 3.3V
- TX/RX pins are directly connected to MCU pins
- In case there is a reset IC between easyDSP /RESET and MCU /XRS, it should transfer easyDSP /RESET signal to MCU /XRS within 0.5sec
- In case you insert buffer IC between easyDSP header and MCU, place buffer IC directly to easyDSP header so that all resistors can be connected to directly MCU
- /BOOT pin is connected to SCITXDA via 2kΩ series resistor
- /RESET pin is connected to reset generation circuit of MCU board
(Time duration of /RESET pin is around 500msec)
- In case you use pull-up resistor to each pin, the value of pull-up resistor should be higher than a few kilo ohm since there is 100Ω series resistor inside easyDSP pod

Please be careful when you use your own pull-up or pull-down resistor on the easyDSP signal pins. Please use appropriate filter circuit to your reset generation circuit to prevent unintentional reset generation.