--- /dev/null
+Notes on Various things I've learned about SDCC and the FX2
+
+* libusb on Linux
+* cycfx2prog: http://www.triplespark.net/elec/periph/USB-FX2/software/index.html
+ - most of this functionality is now in the fx2load package for python
+ - which is in examples/fx2
+* sdcc has sdcc/support/scripts/keil2sdcc.pl which I used to create the fx2regs.h file from the keil header.
+* sdcc is little endian, keil is big endian (important if doing usb communication)
+* xdata can go up to 64k on the EZ-USB development board but
+ - the fx2 chip itself only has 16k (end at 0x4000) Firmware written for other than the dev board
+ - should use --xram-size --xram-loc etc to make sure it isn't using memory beyond 16k.
+* linux has objcopy, which can be used in place of Hex2bix for bix files
+ - objcopy -I ihex -O binary --pad-to=8192 input [output]
+
+
+Memory
+ * 256 bytes internal
+ - lower 128=registers/bits (direct or indirect)
+ - upper 128=stack (or whatever but only indirect addressing)
+ - sfs occupy upper 128 space only direct addressing
+
+ * external
+ - 16k on chip 0-0x3fff
+ - 512 bytes on chip scratch ram 0xe000 - 0xe1ff (data memory only)
+ - epbuffers and control at 0xe200-0xffff (data memory only)
+
+ Only the on chip 16k and 512 bytes can be uploaded w/ eeprom or downloaded to host with SETUPPTR
+ Might be possible to load the descriptors to the scratch ram instead of code ram area?
+
+sdcc data types
+ data/near=direct addressable internal memory (default for model-small)
+ xdata/far=external ram (default for model-large)
+ idata=indirect addressable internal memory
+ pdata=access to xdata area, but uses sfr to get to address (sdcc 4.1)
+ code=code memory, study this more.
+ bit=uses lower 128 bit area
+
+
+TODO:
+ * Possibly add CKCON and bmSTRETCH customization
+ * IN2CLR and INT4CLR registers can be used intead of explicitly clearing int2 and int4 interrupts. (Faster)
+ See (15.5)
projects / sigrok-firmware-fx2lafw.git / blobdiff