Re: [Sdcc-user] How to interface Ricoh RS5C372A RTC with 8051 using i2C
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From: Gudjon I. Gudjonsson <gudjon@gu...> - 2008-07-02 13:49:13
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Hi > Would anyone have an example about how to interface rs5c372a with 8051 > via i2c protocol? I tried to use > http://sdccokr.dl9sec.de/dld/top03_pac01.zip with no luck. > i2c_write() always failed. The RS5C372A slave address is 0x64. > Thanks in advance. > > rs5c372a datasheet: http://www.datasheetcatalog.org/datasheets/480/482022_DS.pdf I made the attached library for my applications on the p89c668 microcontroller, but it has worked with all I2C chips I have used. Sorry, I haven't got time to explain more but I hope it works. There are no error checks in the code. I did not find any solution around different implementation for the last byte written. Cheers Gudjon |
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From: dave jones <s.dave.jones@gm...> - 2008-07-02 13:29:17
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Hello there, Would anyone have an example about how to interface rs5c372a with 8051 via i2c protocol? I tried to use http://sdccokr.dl9sec.de/dld/top03_pac01.zip with no luck. i2c_write() always failed. The RS5C372A slave address is 0x64. Thanks in advance. rs5c372a datasheet: http://www.datasheetcatalog.org/datasheets/480/482022_DS.pdf Best regards, Dave. |
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From: Gudjon I. Gudjonsson <gudjon@gu...> - 2008-07-02 13:49:13
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Hi > Would anyone have an example about how to interface rs5c372a with 8051 > via i2c protocol? I tried to use > http://sdccokr.dl9sec.de/dld/top03_pac01.zip with no luck. > i2c_write() always failed. The RS5C372A slave address is 0x64. > Thanks in advance. > > rs5c372a datasheet: http://www.datasheetcatalog.org/datasheets/480/482022_DS.pdf I made the attached library for my applications on the p89c668 microcontroller, but it has worked with all I2C chips I have used. Sorry, I haven't got time to explain more but I hope it works. There are no error checks in the code. I did not find any solution around different implementation for the last byte written. Cheers Gudjon |
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From: dave jones <s.dave.jones@gm...> - 2008-07-02 13:55:59
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Hi, Thanks for the quick reply. The i2c implementation I mentioned has an error code check, and I think the part of the code is almost the same with yours. I guess my problem is whether I set the wrong slave address or I miss something? Thanks. Regards, Dave. On Wed, Jul 2, 2008 at 9:49 PM, Gudjon I. Gudjonsson wrote: > Hi >> Would anyone have an example about how to interface rs5c372a with 8051 >> via i2c protocol? I tried to use >> http://sdccokr.dl9sec.de/dld/top03_pac01.zip with no luck. >> i2c_write() always failed. The RS5C372A slave address is 0x64. >> Thanks in advance. >> >> rs5c372a datasheet: http://www.datasheetcatalog.org/datasheets/480/482022_DS.pdf > I made the attached library for my applications on the p89c668 > microcontroller, but it has worked with all I2C chips I have used. > Sorry, I haven't got time to explain more but I hope it works. There are > no error checks in the code. I did not find any solution around different > implementation for the last byte written. > > Cheers > Gudjon > > ------------------------------------------------------------------------- > Sponsored by: SourceForge.net Community Choice Awards: VOTE NOW! > Studies have shown that voting for your favorite open source project, > along with a healthy diet, reduces your potential for chronic lameness > and boredom. Vote Now at http://www.sourceforge.net/community/cca08 > _______________________________________________ > Sdcc-user mailing list > Sdcc-user@... > https://lists.sourceforge.net/lists/listinfo/sdcc-user > > |
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From: Dave McGuire <mcguire@ne...> - 2008-07-02 15:08:53
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On Jul 2, 2008, at 9:49 AM, Gudjon I. Gudjonsson wrote: >> Would anyone have an example about how to interface rs5c372a with >> 8051 >> via i2c protocol? I tried to use >> http://sdccokr.dl9sec.de/dld/top03_pac01.zip with no luck. >> i2c_write() always failed. The RS5C372A slave address is 0x64. >> Thanks in advance. >> >> rs5c372a datasheet: http://www.datasheetcatalog.org/datasheets/ >> 480/482022_DS.pdf > I made the attached library for my applications on the p89c668 > microcontroller, but it has worked with all I2C chips I have used. The P89C66x processors have an on-chip I2C controller. What 8051 implementation is the original poster using? -Dave -- Dave McGuire Port Charlotte, FL |
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From: dave jones <s.dave.jones@gm...> - 2008-07-03 05:54:16
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Hi Dave, I want to read/set RTC date and time with 8051 via the i2c protocol. I2C implementation protocol I used is http://sdccokr.dl9sec.de/dld/top03_pac01.zip Also, I found out there are no ouput voltage with the SDA pin, I should set SDA = 0. I guess that i2c implementation I got is wrong? Thanks. Dave McGuire wrote: > On Jul 2, 2008, at 9:49 AM, Gudjon I. Gudjonsson wrote: >>> Would anyone have an example about how to interface rs5c372a with >>> 8051 >>> via i2c protocol? I tried to use >>> http://sdccokr.dl9sec.de/dld/top03_pac01.zip with no luck. >>> i2c_write() always failed. The RS5C372A slave address is 0x64. >>> Thanks in advance. >>> >>> rs5c372a datasheet: http://www.datasheetcatalog.org/datasheets/ >>> 480/482022_DS.pdf >> I made the attached library for my applications on the p89c668 >> microcontroller, but it has worked with all I2C chips I have used. > > The P89C66x processors have an on-chip I2C controller. What 8051 > implementation is the original poster using? > > -Dave > > -- > Dave McGuire > Port Charlotte, FL > > > > ------------------------------------------------------------------------- > Sponsored by: SourceForge.net Community Choice Awards: VOTE NOW! > Studies have shown that voting for your favorite open source project, > along with a healthy diet, reduces your potential for chronic lameness > and boredom. Vote Now at http://www.sourceforge.net/community/cca08 > _______________________________________________ > Sdcc-user mailing list > Sdcc-user@... > https://lists.sourceforge.net/lists/listinfo/sdcc-user > |
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From: Dave McGuire <mcguire@ne...> - 2008-07-03 06:34:05
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On Jul 3, 2008, at 1:54 AM, dave jones wrote: > I want to read/set RTC date and time with 8051 via the i2c protocol. > I2C implementation protocol I used is > http://sdccokr.dl9sec.de/dld/top03_pac01.zip Yes, this is a "bit bang" implementation of the I2C protocol. > Also, I found out there are no ouput voltage with the SDA pin, I > should set SDA = 0. > I guess that i2c implementation I got is wrong? Thanks. What actual chip are you using, what part number from what manufacturer? I'm assuming it's not an actual Intel 8051. The bit-bang code you referenced above is written to use two Port 3 pins as I2C's SDA and SCL signals. Since the I2C protocol depends upon other chips pulling down the SDA line occasionally (ACK bit, etc), you need to make sure you're using I/O pins that'll work for I2C use. They need to be open-drain outputs, not full-totem-pole outputs. For open-drain lines, you'll need external pullup resistors, typically 4.7K or 10K ohm. Standard mcs51 implementations have on-chip pullup resistors on all Port 3 pins. Full totem-pole output drivers, which can either pull a pin to a hard 1 or 0 because they have a FET for each state, just plain won't work for I2C. The standard 8051's output drivers have a FET that can pull a line down to a 0, and on-chip pullup resistors to create a 1. The exception to this is the pins of Port 0, are open-drain outputs with no on-chip pullup resistors, so they can't pull the line up to a 1 by themselves. (when in normal I/O mode, that is...they have pullup FETs which become active when Port 0 is used for external memory access) So anyway, double check the I/O port pin types that you're using. Do you have access to an oscilloscope? -Dave -- Dave McGuire Port Charlotte, FL |
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From: Jean-Paul <tchainick@fr...> - 2008-07-03 07:52:24
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Hello Dave, an afterthought: before you try and implement a protocol with multiple configuration bytes and answer-response traffic, you may want to make sure that a one-byte message does get through to the I2C device. You could use a PCF8574 (or PCF8574A with the alternate address) and simple led-resistor loads on the totem-pole (20mA source and sink) outputs to check the physical bus. Jean-Paul Le Jeudi 3 Juillet 2008 07:54, dave jones a écrit : > Hi Dave, > > I want to read/set RTC date and time with 8051 via the i2c protocol. > I2C implementation protocol I used is > http://sdccokr.dl9sec.de/dld/top03_pac01.zip > Also, I found out there are no ouput voltage with the SDA pin, I > should set SDA = 0. > I guess that i2c implementation I got is wrong? Thanks. -- Tu mangeras quand tu seras compétitif, Mamadou ! -- Never jump into a loop! |
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From: Jean-Paul <tchainick@fr...> - 2008-07-03 06:04:13
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Hello Dave, A stupid question: did you check your hardware and confirm that the two I2C physical lines have got pullup resistors? The outputs of I2C devices are open collectors (rather open drains nowadays). The first question in fact: is there some I2C device that actually works in your hardware? Jean-Paul Le Jeudi 3 Juillet 2008 07:54, dave jones a écrit : > Hi Dave, > > I want to read/set RTC date and time with 8051 via the i2c protocol. > I2C implementation protocol I used is > http://sdccokr.dl9sec.de/dld/top03_pac01.zip > Also, I found out there are no ouput voltage with the SDA pin, I > should set SDA = 0. > I guess that i2c implementation I got is wrong? Thanks. > > Dave McGuire wrote: > > On Jul 2, 2008, at 9:49 AM, Gudjon I. Gudjonsson wrote: > >>> Would anyone have an example about how to interface rs5c372a with > >>> 8051 > >>> via i2c protocol? I tried to use > >>> http://sdccokr.dl9sec.de/dld/top03_pac01.zip with no luck. > >>> i2c_write() always failed. The RS5C372A slave address is 0x64. > >>> Thanks in advance. > >>> > >>> rs5c372a datasheet: http://www.datasheetcatalog.org/datasheets/ > >>> 480/482022_DS.pdf > >> > >> I made the attached library for my applications on the p89c668 > >> microcontroller, but it has worked with all I2C chips I have used. > > > > The P89C66x processors have an on-chip I2C controller. What 8051 > > implementation is the original poster using? > > > > -Dave > > > > -- > > Dave McGuire > > Port Charlotte, FL > > -- Never jump into a loop! |
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From: dave jones <s.dave.jones@gm...> - 2008-07-03 12:59:00
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Jean-Paul wrote: > > Hello Dave, Hi Jean-Paul, > A stupid question: did you check your hardware and confirm that the two I2C > physical lines have got pullup resistors? Yes, both i2c lines have got pull-up resistors. > The outputs of I2C devices are open collectors (rather open drains nowadays). > > The first question in fact: is there some I2C device that actually works in > your hardware? No, there's only one i2c device e.g. rtc on my hardware :-( > Jean-Paul Regards, Dave. |