Hi,
I managed to get AmForth RISC-V running on a SparkFun RED-V Thing Plus [1]
which is based on the same/similar SiFive RISC-V FE310 SoC as on the now
discontinued HiFive1 board [2]
amforth 7.0 RV32IM RED-V Thing Plus
Wed Oct 11 21:25:54 BST 2023
> words
forth-wordlist environment riscv-wordlist @cycle dump .8hex .4hex
.2hex ?ascii type0 hifive-turnkey rev-info build-info mtimecmp mtime
black magenta cyan yellow white blue green red led-init cacheflush
inflash? c!i !i serial-emit? serial-emit serial-key? serial-key
serial-lastchar +usart ram-wordlist wordlist Udefer! Udefer@ dp >in 0>
get-current >body wlscope variable to ; : ] reveal recurse ?abort
postpone +loop newest loop latest header endloop do (create) defer!
defer@ create constant :noname char ['] [compile] [char] \ abort"
abort ' turnkey immediate leave >l l> lp lp0 repeat again else if
while until then begin ahead words sliteral s, ." s" itype type count
ver init-ram ?do map-stack interpret recognize cfg-recognizer
forth-recognizer split rectype-split rec-split rec-num rectype-dnum
rectype-num rectype-xt rec-find rectype-null set-base bases number
>number digit? toupper within ud* m+ name>flags name>string
search-wordlist current show-wordlist traverse-wordlist nfa2cfa
nfa>lfa find-xt cfg-order c, , compile literal 2literal /string parse
parse-name cskip cscan ?stack source-tib source throw catch handler
.ready .ok .input .error ?crlf bs accept refill-tib refill .s ud.r
ud. u. d. d.r . sign #> #s # <# hold hld allot here pad hex decimal (
[ spaces space bl cr ms warm false true -1 4 2 1 0 nr> n>r compare 1ms
up! up@ aligned j i unloop bounds nop pause emit? emit key? key
execute quit cold #tib tib state cells cell+ 2/ 2* 2- 2+ 1- 1+ - +
base d0= d0< ud/mod um/mod s>d 2dup d- d+ dnegate dabs d2/ d2* 2r> 2>r
2r@ 2over 2drop 2nip 2swap umax umin max min = <> u> u< u<= u>= > < <=
>= 0< 0<> 0= c! c@ +! fill move lshift rshift invert not xor or and
rdrop rdepth depth /mod u/mod mod / m* um* * abs negate ! @ sp0 sp sp!
sp@ rp rp! rp@ r@ r> >r pick -rot tuck ?dup rot over nip dup swap drop
exit ok >
I needed to make a few changes to the existing code to get it to
run. Flashing AmForth to the SparkFun RED-V Thing Plus is simple, as
when plugged in it presents itself as a drive. Copy the hex file to
the drive and it flashes itself.
On reset a bootloader runs the copied and flashed AmForth hex file,
but it sends some AT commands over the usart prior to running the
flashed program. It may do other things too. A search suggests this
might be related to a WiFi/BT chip on the HiFive1 Rev B. [3] Remaking
AmForth for a 115200 uart shows this nicely.
ATE0--> Send Flag error: #0 #0 #0 #0 AT+BLEINIT=0--> Send Flag error: #255 #255
#255 #255 AT+CWMODE=0--> Send Flag error: #255 #248 #0 #0
amforth 7.0 RV32IM RED-V Thing Plus
Thu Oct 12 21:48:35 BST 2023
>
I know next to nothing about risc-v assembly, but Matthias' code/macros look
super elegant to me.
COLON "hifive-turnkey", APPLTURNKEY
.word XT_LED_INIT
.word XT_DECIMAL
.word XT_INIT_USART
.word XT_DOT_VER, XT_SPACE
.word XT_ENV_BOARD,XT_TYPE, XT_CR
.word XT_BUILD_INFO,XT_TYPE
.word XT_SPACE, XT_REV_INFO, XT_TYPE
.word XT_EXIT
The SparkFun RED-V Thing Plus has a different LED arrangement and
location but it was easy enough to cobble together some assembler
words to make a proof of blinky.
CODEWORD "led-init", LED_INIT
li x20, 1 << 5
li x21, GPIO_OUTPUT_EN
sw x20, 0(x21)
li x20, 1 << 5
li x21, GPIO_PORT
sw x20, 0(x21)
NEXT
CODEWORD "+led", PLUSLED
li x20, 1 << 5
li x21, GPIO_PORT
sw x20, 0(x21)
NEXT
CODEWORD "-led", MINUSLED
li x20, 1 << 5
li x21, GPIO_PORT
sw zero, 0(x21)
NEXT
I'm glad I started with the SparkFun RED-V Thing Plus board. Whilst
it's more expensive than some other offerings, having something close to
the board AmForth RISC-V was originally written for, definitely helps a
lot. RISC-V is not an "open-source processor" [4] and I'm not able to
cope with the variety yet, if ever.
Despite the product page "backorder" status, there are quite a few of
the SparkFun RED-V Thing Plus still available from the usual sources.
Well a lot of fun, plenty to study for the winter, and with a blinky
up-and-running there is always the hope of progress.
Best wishes,
Tristan
[1] https://www.sparkfun.com/products/15799
[2] https://www.sifive.com/boards/hifive1
[3] https://www.sifive.com/boards/hifive1-rev-b
[4]
https://riscv.org/blog/2020/02/risc-v-is-not-an-open-source-processor-krste-asanovic-chairman-of-the-board-risc-v/
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