Microcontroller with I2C AND robust clock stretching?

Started by Anonymous in comp.arch.embedded14 years ago 4 replies

Does anyone know of an 8-bit microcontroller (among PICs, 8051s, MC68XX, Atmel) that has a built-in i2c module which does the following: ** As...

Does anyone know of an 8-bit microcontroller (among PICs, 8051s, MC68XX, Atmel) that has a built-in i2c module which does the following: ** As a i2c slave device, it's module automatically stretches the i2c clock (SCL) during both a WRITE and a READ by the master? (I currently am using PICs, and clock stretching does not automatically occur when the master does a WRITE. Thus I have a bit ...


Convert digital LCD signal to RGB signal for CRT display

Started by John Tan in comp.arch.embedded16 years ago 1 reply

Hi, I'm working on using Intel PXA255 to have simultaneous LCD panel & CRT display capability. How do we convert the digital LCD signals...

Hi, I'm working on using Intel PXA255 to have simultaneous LCD panel & CRT display capability. How do we convert the digital LCD signals to the analog RGB for CRT display. Namely from the PXA255 LCD controller outputs are: L_FCLK : Frame clock L_BIAS : AC Bias / data enable L_LCLK : Line clock L_PCLK : Pixel clock L_DD[15:0] : pixel_data There are dedicated EPSON graphics co...


SPI Clock pulse problem on ARM Processor

Started by Chandra in comp.arch.embedded12 years ago 1 reply

Hi Guys, I am working on ARM based processor (IMX31). I am having problem with the SPI interface which i am using to interface with the...

Hi Guys, I am working on ARM based processor (IMX31). I am having problem with the SPI interface which i am using to interface with the other devices. Here my problem is when i make a write operation to the SPI, the data pulse is getting started before the clock pulse which is not required. Both the clock pulse and the data pulse should start at the same time. Hope you guys understand my p...


processor clock cycle per instructions

Started by faz in comp.arch.embedded12 years ago 13 replies

Hai all, Can u pls suggest the method or formula to calculate number of processor clock cycles for each instructions ?It will be greatful...

Hai all, Can u pls suggest the method or formula to calculate number of processor clock cycles for each instructions ?It will be greatful to knew this as i have referred the Intel data sheets which includes.I am eager to knew how they r calculating it. regards, fazal


80MHz clock, discrete logic

Started by Steve at fivetrees in comp.arch.embedded13 years ago 20 replies

Hi folks, I have a fairly simple synchronous logic circuit, using a handful of flipflops and gates, which ordinarily I'd breadboard using HC...

Hi folks, I have a fairly simple synchronous logic circuit, using a handful of flipflops and gates, which ordinarily I'd breadboard using HC TTL. However, it needs an 80MHz clock, which is too high for such families. I suspect I might need to look at FPGAs, CPLDs etc, but it's been a long time since I looked at these, and my timescales are short. Could anyone suggest either a family ...


SiLabs C8051F34x and baud rate generation from internal oscillator

Started by Anonymous in comp.arch.embedded12 years ago 3 replies

I know that this IC is able to be used with its internal oscillator when it is used for a USB clock with clock recovery to make it work, however...

I know that this IC is able to be used with its internal oscillator when it is used for a USB clock with clock recovery to make it work, however can the internal oscillator be used for clocking the UARTS, I need one of the 2 of them to run as fast as it can! which I read is / 16 or 3Mhz... on receive. Anyone know the answer... very hard to dig this one up. Richard.


TFT modules with _minimum_ clock frequency spec

Started by Didi in comp.arch.embedded13 years ago

I have been looking around for a TFT module for a design (5" to 8" sized, 800x480 min.,thin) and found some really good looking. The problem I...

I have been looking around for a TFT module for a design (5" to 8" sized, 800x480 min.,thin) and found some really good looking. The problem I have is that some of them specify a minimum dot clock frequency, typically well above 25 MHz. Now apart from a PLL they may have inside the module I can think of little reasons why they need that; and I have not heard of such a thing, but I am far...


CPU AND peripheral clocks

Started by vivek in comp.arch.embedded12 years ago 9 replies

Why are peripheral clocks divided by 2 or 4 or by 8 times of the CPU clock? Why can't they run at CPU core clock speed? This is just a...

Why are peripheral clocks divided by 2 or 4 or by 8 times of the CPU clock? Why can't they run at CPU core clock speed? This is just a general question and not restricted to any processor or architecture.


Simple Clockable Decoder Chip

Started by in comp.arch.embedded12 years ago 34 replies

Let's say we have an 8-Bit shift register. We reset it so that its outputs are as follows: 00000000 We then set the data input high...

Let's say we have an 8-Bit shift register. We reset it so that its outputs are as follows: 00000000 We then set the data input high and clock it: 10000000 We then drop the data input low and continuously clock it: 01000000 00100000 00010000 00001000 00000100 00000010 00000001 This is done easily using two pins from a microcontroller, o...


looking for LCD

Started by Remis Norvilis in comp.arch.embedded14 years ago 3 replies

I am looking for 5 passive monochrome grapchics LCDs, with following specs: 5.7" diagonal 320x240 Operating temp 0C to 50C Viewing Angle 12...

I am looking for 5 passive monochrome grapchics LCDs, with following specs: 5.7" diagonal 320x240 Operating temp 0C to 50C Viewing Angle 12 o'clock (or 6 o'clock) NO integrated controller Integrated backlight (CCFL or LED) Price is my primary concern. But I'd like to avoid obsolete LCDs, or ripped of some used devices, as the product might have a small volume (10 -50) production over ne...


RTL8019AS clock question

Started by Matt in comp.arch.embedded13 years ago 3 replies

Hello all, The data sheet for the RTL8019AS is a bit vague about the clock requirments. After emailing realtek and waiting a week for a...

Hello all, The data sheet for the RTL8019AS is a bit vague about the clock requirments. After emailing realtek and waiting a week for a response they answered most of my questions (20MHz, 16pF load impedence,


Jtag clocks

Started by linnix in comp.arch.embedded13 years ago 12 replies

I am having problem jtag an ARM Cortex M3 at more than 1/256 of the system clock (6Mz). If I clock it any faster, the chip reports data overrun...

I am having problem jtag an ARM Cortex M3 at more than 1/256 of the system clock (6Mz). If I clock it any faster, the chip reports data overrun error. Is there any solution to speed it up? I can jtag an AVR at full speed, so I don't think it's a jtag problem.


Maximum speed, all ports as I/O

Started by in comp.arch.embedded12 years ago 7 replies

At the moment I'm using the following with my PIC16F684: __CONFIG(FCMDIS & IESODIS & BORDIS & UNPROTECT & MCLRDIS & PWRTEN & WDTDIS &...

At the moment I'm using the following with my PIC16F684: __CONFIG(FCMDIS & IESODIS & BORDIS & UNPROTECT & MCLRDIS & PWRTEN & WDTDIS & INTIO); With this setting, the CPU clock is running at 4 MHz. I've heard tho that it can run at 16 MHz. (I'm not using an external clock). Does anyone know what I've to do to get it running at its top speed, and with all pins set to I/O? (I've looke...


Atmega Internal clock source accuracy

Started by eeh in comp.arch.embedded14 years ago 6 replies

Hi, I find that Atmega internal 1MHz RC clock source is inaccurate. It is about 95% of 1MHz. I used 3V. I have tried to check the...

Hi, I find that Atmega internal 1MHz RC clock source is inaccurate. It is about 95% of 1MHz. I used 3V. I have tried to check the oscillator calibration byte by AVRStudio and then load the value into OSCCAL in the beginning of the program. However, the problem is still present. Could anyone tell me how to calibrate under this condition?


OV6680 trouble to start.

Started by jejmule in comp.arch.embedded10 years ago 1 reply

Hello, I am using the omnivision evaluation board, please find the scheme here : http://img32.imageshack.us/i/ov6680sensor.pdf/ My is that...

Hello, I am using the omnivision evaluation board, please find the scheme here : http://img32.imageshack.us/i/ov6680sensor.pdf/ My is that i can't start the chip. What i provide to the board : Vdd : 2.8V ; GND A sin clock at 20Mhz on XCLK PWDN is pull down. The other pin are float. What happen : Nothing What i except : signal on Dato 0..7 and vsync, href and pixel clock. I...


AT91RM900 USART problem

Started by Anonymous in comp.arch.embedded14 years ago 11 replies

We have been developing code for the AT91RM9200 and have found problems with the UART when running the USART 1.5% slower than the selected boaud...

We have been developing code for the AT91RM9200 and have found problems with the UART when running the USART 1.5% slower than the selected boaud rate. A natural consequence with certain clocks and the available divisors available. The problem is that framing errors are not correctly detected. i.e for 115200 we have a 18.432 MHz crystal clock, and processors runs at 179.712MHz, main clock=59....


Difference between Hardware and Software pll

Started by Ali in comp.arch.embedded12 years ago 3 replies

Folks, We are in process to design a device with different sub- device, by sub-devices i mean with different clock requirements....

Folks, We are in process to design a device with different sub- device, by sub-devices i mean with different clock requirements. The main processor we are considering to use comes with software configurable pll, that means you can actually classify the clock for fast, medium and slow devices. But there are some other cheap ICs out there doing the same job while multiplying/dividin...


Merits of software real time clock.

Started by Joseph Casey in comp.arch.embedded15 years ago 6 replies

Greetings. I have a small process control setup running in a single MSP430 uC. The process has certain scheduled tasks, so I wrote a...

Greetings. I have a small process control setup running in a single MSP430 uC. The process has certain scheduled tasks, so I wrote a clock/calendar into the program using the WDT to generate a 1 sec interrupt. The process is important but not safety critical. Consequences of processor crash are repeat of up to 24 hours work plus consternation from the production supervisor. Is it advis...


Signs of bad IC?

Started by cars...@gmail.com in comp.arch.embedded13 years ago 4 replies

Hey all, I'm in a microcomputer hw/sw class where we are building a microprocessor board using an 8088. I wire wrapped the clock circuit and...

Hey all, I'm in a microcomputer hw/sw class where we are building a microprocessor board using an 8088. I wire wrapped the clock circuit and the reset circuit before testing it with the 8088 in its socket, and all seemed to be fine (voltage tests, and frequency on the clock). When I put the 8088 in its socket I was getting a short between VCC and Ground on the power supply. When I remove...


AVR EEPROM Endurance

Started by Greg Schaefer in comp.arch.embedded16 years ago 8 replies

I was wondering if anyone has experience with EEPROM endurence on Atmel AVR parts. I have a controller project that requires a real-time...

I was wondering if anyone has experience with EEPROM endurence on Atmel AVR parts. I have a controller project that requires a real-time clock that I originally planned to implement via a DS1320+supercap. However, I recently found a prebuilt board that does 90% of what I want but does not include a battery/cap backup RTC. I can use one of the AVR timers to generate an accurate clock while i...