Re: [Gumstix-users] non-standard baud rates

 Re: [Gumstix-users] non-standard baud rates From: Craig Hughes - 2005-01-31 02:58:24 ``` =46rom the PXA Processor Developer's guide: 10.4.2.3 Divisor Latch Registers (DLL and DLH) Each UART contains a=20 programmable baud rate generator that can take the 14.7456 MHz fixed =20 input clock and divide it by 1 to (216=961). For the FFUART and the=20 STUART, the divisor is from 4 to (216=961). The baud rate generator=20 output frequency is 16 times the baud rate. Two 8-bit latch registers,=20= shown in Table 10-5 and Table 10-6, store the divisor in a 16-bit=20 binary format. Load these divisor latches during initialization to=20 ensure that the baud rate generator operates properly. If each Divisor=20= Latch is loaded with a 0, the 16X clock stops. The Divisor Latches are=20= accessed with a word write. The baud rate of the data shifted in to or=20= out of a UART is given by the formula: [picture of formula] For=20 example: if the divisor is 24, the baud rate is 38400 bps. The=20 divisor=92s reset value is 0x0002. For the FFUART and the STUART, the=20 divisor must be set to at least 0x0004 before the UART unit is=20 enabled. The formula in question is baudrate =3D 14.7456MHz/(16xdivisor), ie divisor =3D (14.7456*10^6)/(16*baudrate) (14.7456*10^6)/(16*31250) =3D 29.49 So you'd have to choose 29 or 30 14.7456M/16*29 =3D 31779 14.7456M/16*30 =3D 30720 setserial should work I think for either of those values. C On Jan 30, 2005, at 5:55 PM, Darren Gibbs wrote: > Would it be fantastically tricky to get gumstix to do non-standard=20 > baud rates on a uart? I'm thinking of MIDI (31250). > > > > ------------------------------------------------------- > This SF.Net email is sponsored by: IntelliVIEW -- Interactive = Reporting > Tool for open source databases. Create drag-&-drop reports. Save time > by over 75%! Publish reports on the web. Export to DOC, XLS, RTF, etc. > Download a FREE copy at http://www.intelliview.com/go/osdn_nl > _______________________________________________ > gumstix-users mailing list > gumstix-users@... > https://lists.sourceforge.net/lists/listinfo/gumstix-users ```