How was it discovered that the Dreamcast Serial port could be used for SPI?

Post by **SegaSagas** » Mon Mar 14, 2022 9:45 pm

I know It's old news but it's still technically impressive, in the early days the only hobbyist uses for the serial port was a coder's cable which used rs232 at ttyl iirc & that isn't compatible with SPI at all. I know other devices can bit bang on gpio but Dreamcast doesn't have gpio right?

Post by **megavolt85** » Tue Mar 15, 2022 5:24 am

SegaSagas wrote:I know other devices can bit bang on gpio but Dreamcast doesn't have gpio right?

Post by **fafadou** » Tue Mar 15, 2022 7:01 am

Same gpio type as raspberry pi ?

Post by **megavolt85** » Tue Mar 15, 2022 4:40 pm

GPIO he and in vacuum cleaner GPIO

Post by **SegaSagas** » Sat Mar 19, 2022 2:45 am

megavolt85 wrote:
SegaSagas wrote:I know other devices can bit bang on gpio but Dreamcast doesn't have gpio right?
DC GPIO.jpg

Huh, you learn something new every day, still makes me wonder about SPI over the serial port.

Post by **sundance** » Thu Apr 13, 2023 5:11 am

Has anyone attempted to use the SPI to communicate over the serial port ?
Specifically, to read data from a SD Card connected via the serial port ?

Some say it could achieve faster speeds and be more energy friendly than cpu bit-banging,
however I would like to see it to believe it.

Post by **megavolt85** » Fri Apr 14, 2023 11:51 am

sundance wrote:Has anyone attempted to use the SPI to communicate over the serial port ?
Specifically, to read data from a SD Card connected via the serial port ?

Serial port cannot work in SPI mode, only SPI bitbang is possible

sundance wrote: Some say it could achieve faster speeds and be more energy friendly than cpu bit-banging,

They give out what they want
In DreamCast, only one port knows how to work in SPI, this is SCI (not to be confused with Scif on the rear panel), the maximum speed of the SCI 5 Mbps, provided an external clock signal, the SPI bitbang speed is about 7 Mbps

Dreamcast-Talk.com

How was it discovered that the Dreamcast Serial port could be used for SPI?

How was it discovered that the Dreamcast Serial port could be used for SPI?

Re: How was it discovered that the Dreamcast Serial port could be used for SPI?

Re: How was it discovered that the Dreamcast Serial port could be used for SPI?

Re: How was it discovered that the Dreamcast Serial port could be used for SPI?

Re: How was it discovered that the Dreamcast Serial port could be used for SPI?

Re: How was it discovered that the Dreamcast Serial port could be used for SPI?

Re: How was it discovered that the Dreamcast Serial port could be used for SPI?