Serial driver for 4G+ ipods

[Jacob83]

Hi guys,
I cant understand, why it is that complicated to implement a serial driver. I think you have to know the register for the  baudrate and anythin else is done by hardware... isn't it??
I would really enjoy my ipod mini with serial port for my homebre gadgets...
regards, Jacob
http://www.avr-projects.info

[Llorean]

If it's easy, we look forward to your patch soon.
If you aren't both capable of doing it and plan on doing it, kindly shut up. Saying "it ought to be easy" doesn't accomplish anything. Especially when how easy something in doesn't always even factor into whether it gets done or not.

[Jacob83]

Hmm...
but don't you think the only thing to do is to write some (<5) Bytes into some registers, that are at the moment not known? Or can you tell me what complicates this task?
thanks, Jacob

[saratoga]

I believe no one has looked into implementing the serial port driver.  It may be easy or hard, we just don't know.

[Jacob83]

Okay, i am nearly sure, that the only problem are the adresses of the registers...
I found this in the sources of ipodlinux (serial.h)
I found as well a log of an irc chat about this issue, see http://rainstorm.org/ipod/stats/ipodlinux.log-2006-08-16
but unfortunately i don't know that much about arms... so i'll have to wait for someone to find out how it works on newer ipod generations.
regards,
Jacob

Code: [Select]

/* PP5002 */
#define PP5002_IPOD_SER0_BASE 0xc0006000
#define PP5002_IPOD_SER1_BASE 0xc0006040
/* PP5020 */
#define PP5020_IPOD_SER0_BASE 0x70006000
#define PP5020_IPOD_SER1_BASE 0x70006040
/* The UART is clocked at 24MHz */
#define BASE_BAUD (24576000 / 16)
#define STD_COM_FLAGS (ASYNC_BOOT_AUTOCONF|ASYNC_SKIP_TEST)
#define DEFAULT_CFLAGS (B9600 | CS8 | CREAD | HUPCL | CLOCAL)
#define RS_TABLE_SIZE 2
#define STD_SERIAL_PORT_DEFNS \
{ \
magic: 0, \
baud_base: BASE_BAUD, \
irq: PP5002_SER0_IRQ, \
flags: STD_COM_FLAGS, \
type: PORT_UNKNOWN, \
iomem_base: (u8*)PP5002_IPOD_SER0_BASE, \
iomem_reg_shift: 2, \
io_type: SERIAL_IO_MEM \
}, /* ttyS0 */ \
{ \
magic: 0, \
baud_base: BASE_BAUD, \
irq: PP5002_SER1_IRQ, \
flags: STD_COM_FLAGS, \
type: PORT_UNKNOWN, \
iomem_base: (u8*)PP5002_IPOD_SER1_BASE, \
iomem_reg_shift: 2, \
io_type: SERIAL_IO_MEM \
} /* ttyS1 */ 

[AlexP]

but unfortunately i don't know that much about arms

But, it is easy right?  Oh hang on, I guess maybe it isn't.

Coming on these forums and saying, this is easy, why hasn't someone done it (I can't do it myself it is too difficult) isn't going to be well received.

[Jacob83]

compared to some other stuff that has already been acheived it should be possible... if you look at the init sequences in the sources of ipodlinux you'll see  it's just a matter of knowledge about some adresses that are kept secretly in the caves of nvidia   - what a pity.

[AlexP]

Of course it is possible, but unless you have actually done it or are going to, saying something is easy, why haven't you done it will annoy people.

[bluebrother]

Of course it is possible, but unless you have actually done it or are going to, saying something is easy, why haven't you done it will annoy people.

Right.

I did some work with ARM chips before and I'm interested in looking into that issue. But there are a couple of problems:
- the hardware is barely known, which makes it difficult to "just" write a driver
- writing a driver is only a small amount of the work that's needed -- you need to integrate it into Rockbox as well. It's not just writing "some bytes into some register".
- time is usually an issue, which also applies for me
- and in my case, I bought some cheap Ipod accessory to create a serial cable out of it, but unfortunately this thing hasn't arrived yet.

Btw, why are you linking an AVR website?