Under factory default (OTP_BOOTPIN_CONFIG_KEY != 0x5A) and no emulator connected, MCU checks below two pins at reset to determine the booting mode.
|
MODE |
GPIO24 | GPIO32 |
Boot mode |
| Mode 0 | 0 | 0 | Parallel I/O |
| Mode 1 | 0 | 1 | SCI / Wait (RAM boot) |
| Mode 2 | 1 | 0 | CAN |
| Mode 3 | 1 | 1 | Flash (USB) |
easyDSP uses two kinds boot mode, SCI boot
mode for RAM booting, Flash boot mode for flash rom booting.
Therefore, below connection is recommended between easyDSP
and MCU.
If external oscillator is used, 20Mhz
is recommended.
- Factory default
setting is assumed
- power pin (#4) of
easyDSP 5x2 header should be connected to 3.3V
- SCIA_RX = GPIO28, SCIA_TX = GPIO29
- 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
- TX/RX pins are directly connected to
MCU pins
- 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 GPIO24 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.