#avr Logs

Feb 01 2021

04:00 AM vmt: rue_mohr: what, dma?? stm32?? isn't that like F150 gas guzzler! for it has to be, if tiny/mega doesn't have dma, then you don't need it
04:07 AM vmt: dma is the devil's lettuce
05:18 AM twnqx: vmt: on PC it kinda is/was :P
05:18 AM twnqx: if you ever read the datasheet of a 8237 and understood how it did DMA you just want to scream and run
05:28 AM vmt: well lol, 8237 dates back when?
05:29 AM vmt: but we're not talking about even being implementation-specific here, it's just that what's not in a tiny/mega is not needed! pesky dma, who even needs that
05:35 AM twnqx: i suppose the stm32 with its matrix has the bandwidth to do DMA in parallel with cpu core memory access
05:36 AM twnqx: i doubt dma would do any good on an avr
05:36 AM twnqx: hm, unless it's done the PC way
05:37 AM twnqx: where you can single (well, quad, but that's a single access) cycle transfer mem -> io
05:37 AM twnqx: but that only works because the PC has separate mem and IO, which the avr again doesn't have
05:37 AM twnqx: mh
05:38 AM twnqx: no idea.
05:38 AM cehteh: in avr the memoy busses are cycle-locked to the core iirc ... would be quite ugly/unexpected if something else could mess with that
05:39 AM twnqx: yeah, it would definitely be either dma controller or core accessing it
05:39 AM twnqx: but might only need two thirds of the cycles it takes the cpu
05:39 AM twnqx: as decrement/conditional jump takes extra cycles, which a dmac would do in parallel
05:39 AM cehteh: in theory sram could be much faster thus dma could run inbetween the cpu accesses, but still that would become a somewhat different arch
05:40 AM twnqx: yeah... currently pondering 10ns SRAM on my 8086 build :P
05:49 AM vmt: why 8086 or is this for shits and giggles?
06:04 AM twnqx: yeah, shits and giggles
06:05 AM twnqx: or maybe riding on the retro wave, who knows what comes from this
06:06 AM twnqx: basically mini-atx with onboard serial/parallel/usb/usb-ethernet and 4 ISA slots
06:06 AM twnqx: made for 8086/8088 cpus :P
06:07 AM twnqx: blatantly stupid for shits and giggles and against boredom
06:07 AM twnqx: though it's proving difficult to get some of the stuff, e.g. the good old ATX parallel+2xserial connectors
06:09 AM vmt: 6502 gives more street cred than 8086
06:09 AM twnqx: sure, but it's not a PC
06:10 AM twnqx: this is a PC.
06:10 AM vmt: pc's dont give street cred, ibm is evil
06:11 AM vmt: i mean was evil, that's what apple told us. nowadays ibm is just lmao
07:32 AM Helle: twnqx: I mean if you are willing to deal with industrial form factors instead, you can happily get plenty of solutions like that
07:39 AM twnqx: ?
08:23 AM rue_mohr: vmt F103
08:50 AM rue_mohr: twnqx, you need connectors?
08:50 AM rue_mohr: or an isa card?
01:34 PM twnqx: why is my router rbeaking :
01:34 PM twnqx: rue_mohr https://i.imgur.com/m2ff4rh.png this is were i was a bit ago :S
07:02 PM rue_mohr: fun