Firmware

Information regarding the software that is embedded within the H8S/2265 Microprocessor.

Boot Address

 ifdef CYBIKO_CLASSIC
  define CYBIKO_ADDR_RAM   0x00200000
  define CYBIKO_ADDR_CYOS  0x00100000
  define CYBIKO_SIZE_CYOS  0x00040000 
 else
  define CYBIKO_ADDR_RAM   0x00400000
  define CYBIKO_ADDR_CYOS  0x00600000
  define CYBIKO_SIZE_CYOS  0x00080000
 endif

The boot file is stored on a flashrom (model 2 classic and xtreme) at address 0x00100000 (classic) or 0x00600000 (xtreme), the model 1 classic loaded it from serial flash into ram.

An uncompressed boot file should start with a 12 34 AB CD signature.

The AVR 2313 chip acts as a co-processor to the main H8 device. It is used to handle the RF comms aspect of the Cybiko.

The UART on the 2313 is connected to a UART on the main H8 processor, this comms link runs at 53.333KBaud and allows the H8 to control the 2313 via SCI Channel 0 (TXD0 and RXD0). The 2313 is clocked at a modest 4MHz.

Three port pins on the 2313 link to the LMX2315 chip and clock data in and out of this chip.

The files below contain an annotated disassembly of the code that resides in the flash space of the 2313 device. Someday merge both into one.

Programming the AVR

It is possible to program the AVR with new firmware whilst it is insitu inside the Cybiko. This is possbile due to the fact that the MOSI/MISO lines are connected to the H8 on the same lines that the H8 uses to drive the AVR fed RF transmitter.

  • MOSI: The data signal that sends the bits to be written to the AVR,
  • MISO: The data signal that receives the bits read from the AVR.
  • SCK: A clock signal that shifts the bits to be written to the memory into an internal shift register, and that shifts out the bits to be read from another internal shift register

These three signal pins are internally connected to the programming machine only if you change the RESET (sometimes also called RST or restart) pin to zero. Otherwise, during normal operation of the AVR, these pins are programmable I/O lines like all the others.

AVR RST is connected to H8 TMO0 (Port 2, bit 6)
The SCK line of the AVR is held high at 3.3v via a 5.1k resistor.