What are my options - Two uarts needed?

[Wilksey]

Ahh, the voltage difference! So if I supplied my 3.3V pic externally, which I do anyway, and plug in the PIC KIT 2 it would sense no voltage and automatically send 5V down the VDD?

Most of the RFID things i've seen operate over a UART, it sends the ID down as a serial stream.

If you wish to use through hole then you will have to use an 18F with 2 uarts on unless you want to do a software uart.
Wilksey

 

[Mike - K8LH]

Is anyone else at all curious about the combination of MP3 and RFID, or am I the only one (lol)?

 

[Wilksey]

Mike,

Never actually thought about it, until now lol..

Some sort of personalised jukebox? lol

 

[kjennejohn]

Ahh, the voltage difference! So if I supplied my 3.3V pic externally, which I do anyway, and plug in the PIC KIT 2 it would sense no voltage and automatically send 5V down the VDD?

Most of the RFID things i've seen operate over a UART, it sends the ID down as a serial stream.

If you wish to use through hole then you will have to use an 18F with 2 uarts on unless you want to do a software uart.
Wilksey

The PICKit2 has a clickable button on its control window that detects the Vcc present on the target board, IF you have Vcc connected to its appropriate pin. Another selection tells it to supply the Vcc to your circuit, but is only good for 100mA max. This is good for the processor and a few LEDs, say. The 18F25K22's Vcc is good for around 3V to 5V. The early preliminary data sheet says the programming data levels are 3 to 5, also. I have programmed this processor with both. I prefer 5V, though, as all my peripherals are 5V only.
To my mind, hardware USARTs are to be prefered everytime. They don't suffer from lag or dropouts, as they have hardware buffers built in. However, bitbang serial is OK if it is doing output only, ie, a command port for external control of other devices. If you MUST do input with bitbang, you can implement flow control to hold off the other device from sending anything until your processor can get to it.
HTH.
kenjj

 

[be80be]

Why would the op think he would need two uarts the RFID carder reader is only 2400 baud and a VS1011 is spi

And why would the op need RFID that is a little funny

A 3.3 volt chip would be Idea but there are a lot of these using a 16f88 using SD cards and the VS1011

 

[Brevor]

Looks like the OP has moved on again. Two weeks ago he was asking all about a push pull solonoid driver. Last week it was about coding an RGB system, Now it's RFID and MP3. He just stops responding and comes back with a new subject.

 

[Spadez]

Sorry for my lack of reply. My project criteria are changing so I havent been able to reply.

It is now possible to use C. Does this mean there is no difference between using a 16F pic and an 18F pic in terms of required c code?

Secondly, in DIP format, is it fair to say that the PIC18F25K22 is the best contender for dual uarts?

https://uk.farnell.com/microchip/pic18f25k22-i-sp/mcu-8bit-32k-flash-28spdip/dp/1840992

 

[kjennejohn]

Sorry for my lack of reply. My project criteria are changing so I havent been able to reply.

It is now possible to use C. Does this mean there is no difference between using a 16F pic and an 18F pic in terms of required c code?

Secondly, in DIP format, is it fair to say that the PIC18F25K22 is the best contender for dual uarts?

MICROCHIP|PIC18F25K22-I/SP|MCU, 8BIT, 32K FLASH, 28SPDIP | Farnell United Kingdom

Since 16Fs and 18Fs are different internally, there will be differences in the C code.
As for "best contender", define "best". The 18F45K22 has more of everything, and is only slightly more expensive (Digikey, $3.56, singles). A quick Google on "dual UART microprocessors" shows there are 80C51 derivatives and ARM parts that have dual UARTs as well. Whether or not they are DIP, and as affordable, is another question. It never ceases to amaze me how much cr*p manufacturers can stuff into these things.
Later.
kenjj