Fish4Fun
So long, and Thanks for all the Fish!
In the Data Sheet for the ATMEGA2560 the following code example is given to initialize a UART:
Great News....It works! However, later on in the documentation.....
The UMSELn Table Breakdown of the UCSRnC Registers shows:
When it is all said and done, $86 is the most commonly used setting for RS232-TTL type comm, which obviously shows UCSRnC.7 as being Set and USCRnC.6 as being cleared....But the results of the "example code" work perfectly, LoL! Not a huge deal until you run into a comm port that isn't responding correctly and you are pulling your hair out attempting to get it to work.....
For giggles i will point out that the ACTUAL PROBLEM I was having had nothing to do with my code or the UART settings.....Turns out the last batch of ARDUINO 2560 Clones I received have a silkscreen error! LoL, the Rx and Tx pins are mislabeled on UART1 (simply reversed).....It turns out that there isn't a register setting to make the Rx line transmit!
I caught the apparent Atmel Documentation Error while attempting to figure out why I couldn't Tx to a slave device.....Likely the documentation has been updated, or there has been a "Notice" of some sort about the apparent error, but I found the Actual Problem before I found any reference to the contradiction.....
Six hours of my life wasted....but other than that no real harm or foul.
Cheers!
Fish
Code:
Assembly Code Example(1)
USART_Init:
; Set baud rate
sts UBRRnH, r17
sts UBRRnL, r16
ldi r16, (1<<U2Xn)
sts UCRnA, r16
; Enable receiver and transmitter
ldi r16, (1<<RXENn)|(1<<TXENn)
sts UCSRnB,r16
; Set frame format: 8data, 1stop bit
ldi r16, (2<<UMSELn)|(3<<UCSZn0)
sts UCSRnC,r16
ret
(Taken from Page 211, 2549P–AVR–10/2012)Great News....It works! However, later on in the documentation.....
The UMSELn Table Breakdown of the UCSRnC Registers shows:
Code:
Table 22-4. UMSELn Bits Settings
UMSELn1 UMSELn0 Mode
0 0 Asynchronous USART
0 1 Synchronous USART
1 0 (Reserved)
1 1 Master SPI (MSPIM)
(Taken from Page 225, 2549P–AVR–10/2012)When it is all said and done, $86 is the most commonly used setting for RS232-TTL type comm, which obviously shows UCSRnC.7 as being Set and USCRnC.6 as being cleared....But the results of the "example code" work perfectly, LoL! Not a huge deal until you run into a comm port that isn't responding correctly and you are pulling your hair out attempting to get it to work.....
For giggles i will point out that the ACTUAL PROBLEM I was having had nothing to do with my code or the UART settings.....Turns out the last batch of ARDUINO 2560 Clones I received have a silkscreen error! LoL, the Rx and Tx pins are mislabeled on UART1 (simply reversed).....It turns out that there isn't a register setting to make the Rx line transmit!
I caught the apparent Atmel Documentation Error while attempting to figure out why I couldn't Tx to a slave device.....Likely the documentation has been updated, or there has been a "Notice" of some sort about the apparent error, but I found the Actual Problem before I found any reference to the contradiction.....
Six hours of my life wasted....but other than that no real harm or foul.
Cheers!
Fish
