Matrix user forums

Hi. What would be the best way to generate a 32.768khz signal using a PIC. Main crystal is 16Mhz. The signal needs to be a square wave with and amplitude of 3v. Im thinking something interrupt based toggling a output pin. I would prefer not to use additional crystals if i can help it. Would timer 2 ...

Hi, I have a question that I don't seem to be able to find a simple answer for. Imagine we have 2 PIC microcontrollers. 1 of these 8bit and the other 16bit. Both PICs running at the same frequency etc. Both PICs are sending data via SPI to a colour display. The 8bit microcontroller would send 2 byte...

I have just seen that atmel produce other SAM7 chips. In the device list we have for example an AT91SAM7S256, these are now discontinued. However they produce an AT91SAM7X256, These appear to be currently manufactured. Only difference is they have different pin counts, 64 and 100 respectively. Would...

Hi, I was just looking through the chip list in V6 for ARM controllers as I may have a project that would be best suited to ARM due to its 32bit core. Unfortunately it would seem that almost all of them are no longer manufactured. from the list I found 2 that have decent levels of stock at farnell b...

Hi, I meant to do an example of how I did this but forgot about it. Here is the original equation, Temperature (°C) = Temperature Output Count /(2^14 - 1) x 165 - 40 Humidity (%RH) = Humidity Output Count / (2^14 - 1) x 100% In my case here I worked out what 2^14 equalled. in case your not sure how ...

That looks good to me

you could use an external falling edge interrupt on the incoming RX signal to detect the start bit and call the receive function. There will be no buffer using software mode so you will have to be calling the receive function or you will miss the data. If you know that you are sending a certain amou...

Hi Ben, I tried the driver as you said and i cannot get it to work at all. Im not sure if the driver i linked in my first post used the D/C instruction Pin. I saw the driver you posted has a register select pin, i assume this is the same as D/C pin ??? Here is one that uses the D/C instruction Pin. ...

Thanks for that Ben. I will try it when i get home this evening. I realised that the CS pin was wrong and did manage to get the screen to initialise and could plot pixels. I was getting a wierd problem tho. If i create a full white background and then put a pixel in another colour. That row of white...

I am trying to make a driver for a 128 x 128 OLED Display. It uses a SSD1351 Chipset and is driven using SPI. The datasheet for the Display is here. http://www.4dsystems.com.au/downloads/micro-OLED/OLED-128/Docs/Pdf/SSD1351-Revision%201.3.pdf I am using some code as a guide which can be found here. ...

I have figured this out now

Hi, I am wondering if these formulas can be calculated using integer math, I have never worked with powers before so I have no idea how to proceed. Temperature (°C) = Temperature Output Count /(2^14 - 1) x 165 - 40 Humidity (%RH) = Humidity Output Count / (2^14 - 1) x 100% The formulas can be found ...

Hi, I am having a play with the new flowcode 6 demo and I have a custom file I would like to use with it. Is there a way to wrap it into a component?? I have seen it done on another thread but no explanation of how to actually do it. If anyone can do this I can either send the custom file to you, or...

Hi Ben Yes thats what i was looking at. _x0 = (float)ac1; So for the above i do the following?? Convert ac1 to a float X0 = ac1 I think this one would go something like this aswell z = ((float)_pu - x) / y; Convert _pu to float value Z =( _pu -x) / y Would that be correct?? Also one last thing what ...

Hi Im trying to work some floating point math in flowcode but im a little puzzled by a particular part of the math. Here is a large snippet of the code im copying. // calculate floating point cal factors _c3 = 0.0048828125 * ac3; // 160 * pow2(-15) * ac3; _c4 = 0.000000030517578125 * ac4; // 1E-3 * ...

* Function：SetBitMask * Description：set RC522 register bit * Input parameter：reg--register address;mask--value * Return：null */ void SetBitMask(uchar reg, uchar mask) { uchar tmp; tmp = Read_MFRC522(reg); Write_MFRC522(reg, tmp | mask); // set bit mask } /* * Function：ClearBitMask * Description：cle...

I have another question...


How would you deal with this?

WRITE_SPI (Register, Temp | Mask)

and also

WRITE_SPI (Register, Temp & (~Mask))


Mask = 0x80

Temp is a byte read from a read function.


I havnt done masking before so this is a bit new to me.

Thanks for clearing that up ben. Will see if it works when i get home

Hi. Could this be converted to a flowcode chart?? uchar Read_MFRC522(uchar addr) {uchar val;digitalWrite(chipSelectPin, LOW); //address format：1XXXXXX0 SPI.transfer(((addr<<1)&0x7E) | 0x80); val =SPI.transfer(0x00); digitalWrite(chipSelectPin, HIGH); return val; I dont understand where return val i...

Do you understand where the return val variable is being loaded from??

Im using version 3.

Hi. Could this be converted to a flowcode chart?? uchar Read_MFRC522(uchar addr) {uchar val;digitalWrite(chipSelectPin, LOW); //address format：1XXXXXX0 SPI.transfer(((addr<<1)&0x7E) | 0x80); val =SPI.transfer(0x00); digitalWrite(chipSelectPin, HIGH); return val; I dont understand where return val is...

I cant get my head round why the reads are done one after the other, if the interrupt is dissabled how does the i2c carry on receiving data?

Thanks for that Dazz,

So do you know if the i2c receives all the data and then processes it or does it process each byte on the go?

Looking at the code it seems it receives it all first, but i might be wrong there.

Can anyone help with this?