Becoming Deranged
In addition to the Expansion connector on its right hand side the STK3700 has perimeter peripheral and signal pins that can be used for connection.
To use these easily I soldered on some gold connector pins.
To enable the connection of both e-paper and Energy Harvesting modules the following actions were undertaken;
- Solder header pins to perimeter connection pads of the STK3700
- Relocate e-paper connections from Expansion header to the new header pins.
This sounds straightforward except for two hiccups;
- Pin PC6 does not have a designated perimeter connection pin
- Pin PC5 does not have a designated perimeter connection pin
Access to these pins is difficult. They just happen to be both on the bottom row of the expansion connector which is surface mounted thus is not accessible from the bottom side of the PCB.
The solution is to assign new pins which have been allocated peripheral pins that are free for use.
In addition to connection to the newly allocated pins the source code requires this information to be input into its Display_Hardware_GPIO.h header files.
The Busy and EPD_CS definitions were changed (PB10 and PB9 respectively) to their new home (PD14 and PD13).
The code was rebuilt and tested fine.
Keep the wiring together and to enable easy viewing of (STK3700) LCD I also moved the connection from pin PC0 which is at the bottom of the STK3700 to PD15) and rebuilt and tested the code.
This also tested fine.
The freeing up of the expansion connector made it simpler to attach other peripherals to the project.
This picture shows how the Ferromagnetic RAM is connected to the expansion connector.
The Energy Harvesting board can still be connected using a jumper lead that connects the three GNDs, VMCU and PGOOD.
It is currently disconnected whilst I am performing the code development.