I have a program which display as follows .
first Line : Volt : Over Voltage
Second Line : Current : Over Current.
In LCD the cant fully display the letter OVer Voltage or Over Current .
I just want to scroll these . But the Volt : and current : letter will be there that will not need to scroll ?
So you will need to create a routine to cycle thru the messages you want to display.
As an example, first time send "Volt: Over Volta"
Then a second later send "Volt: ver Voltag"
then "Volt: er Voltage" and so on.
The other option would be to create a routine to display the value part with a starting index after determining the len.
The following puesdo code is not compiled/tested.
char buf[17];
char label[]= "Current";
char value[]= "Over Current";
while(1)
{
if (++start_pos >= (strlen(value)+strlen(label)-16)
{
start_pos=0;
delay(500); //ms
}
snprintf(buf,16,"%s: %s",label,value[start_pos]);
puts(buf); // whatever the name of your routine to send string to LCD
if (start_pos==0)
{
delay(500); //ms
}
delay(1000); //ms NOTE: you probably want to go do some other code during this time.
}
You may want to see if you're LCD has a scroll command. Some LCDs have a character buffer where you can write data to then give a scroll command to shift which are displayed. For example I've used an LCD that can store 40 characters per line in DDRAM while displaying only 16. If I remember correctly, you have to scroll both lines at once this way, though.
If this doesn't tickle your fancy, another way is to shift your buffer in code and re-write all of it to the LCD. You can do this fast enough that it doesn't look terrible.
Related
I'm writing 8-bit PIC microcontroller C code in Microchip's MPLAB X tool using their XC8 compiler for a demo / evaluation board for a sensor IC. The PIC I'm using has multiple serial ports, so I'm using UART2 to output only sensor data. I wanted to be able to format the output data for hex or decimal so I have stdio redirected to this port. The Rx side of UART2 is unused.
UART1 is used for command and control. This port needs to be able to output ASCII messages such as "Enter the register address:". The sensor is highly configurable, so my code initializes it with default values, but the user can halt sampling, read and write registers and re-start sampling.
Since I can't use printf when writing to UART1, I had to find another way to do this. Here's an example of what I'm doing. The file is large so I'm just cutting and pasting the relevent stuff here:
char msgString[64];
switch(command)
{
case (READCMD): // Read command
{
if (SERIAL_STATE_IDLE == serialPortState)
{
strcpy (msgString, "Input Read Address Hex Value 00-18");
Display_PrintMessage();
Display_PrintChar(prompt);
serialPortState = SERIAL_STATE_READ;
}
...
void Display_PrintMessage(void)
{
msgLength=strlen(msgString);
for (i=0; i<msgLength; ++i)
{
UART1_Write(msgString[i]);
}
Display_PrintChar(newLine);
}
void Display_PrintChar(char c)
{
UART1_Write(c);
}
I've verified that the port is working by writing some characters out to it early in main and they do appear on my terminal. I think the problem is with how I'm using the strcpy function. In the MPLAB debugger it appears that msgString is still all null characters after the strcpy executes. The strlen function may see msgString as zero length, hence, nothing prints out.
I would love to hear what you think may be wrong with my code, or, please suggest another way of accomplishing what I need.
Thanks in advance for any and all responses, they are much appreciated.
CobraRGuy
I'm doing my first attempt working with linker files. In the end i want to have a variable that keeps it's value after reset. I'm working with an STM32L476.
To achieve this i modified the Linker files: STM32L476JGYX_FLASH.ld and STM32L476JGYX_RAM.ld to include a partition called NOINT.
MEMORY
{
RAM (xrw) : ORIGIN = 0x20000000, LENGTH = 96K
RAM2 (xrw) : ORIGIN = 0x10000000, LENGTH = 32K
FLASH (rx) : ORIGIN = 0x8000000, LENGTH = 1024K -0x100
NOINIT (rwx) : ORIGIN = 0x8000000 + 1024K - 0x100, LENGTH = 0x100
}
/* Sections */
SECTIONS
{
...
/* Global data not cleared after reset. */
.noinit (NOLOAD): {
KEEP(*(*.noinit*))
} > NOINIT
...
In the main.c i initialize the variable reset_count as a global variable.
__attribute__((section(".noinit"))) volatile uint32_t reset_count = 0;
The =0 part is just for simplification. I actually want to set reset_count to zero somewhere in a function.
When i run the program and step through the initialization i would expect to see the value of reset_count as 0. But somehow i always get 0xFFFFFFFF. It seems like i can't edit the reset_count variable. Can anybody tell me how i can make this variable editable?
It is not clear from the question whether you want to have a variable that keeps its value when power is removed, or just while power stays on but hardware reset is pulsed.
If you want something that keeps its value when power is removed, then your linker script is ok to put the block in flash memory, but you need to use the functions HAL_FLASH_Program etc. to write to it, you can't just make an assignment. In addition, you could simplify the linker script by instead of creating the NOINIT output region, just putting >FLASH.
If you want a variable that just persists across reset wile power stays up then you need to put the variable into SRAM not FLASH, for example like this:
.noinit (NOLOAD) :
{
*(.noinit*)
}
> RAM2
Note that you don't need to use KEEP unless you want to link a section that is unreferenced, which will not be the case if you actually use the variables, and you don't need another * immediately before .noinit unless you section names don't start with a ., which they should.
You will not be able to write to the flash memory as simply as that. If you use ST HAL, there is a flash module that provides HAL_FLASH_Program() function.
Alternatively, if the data you are trying to store is 128 bytes or less and you have an RTC backup battery, you can use the RTC backup registers (RTC_BKPxR) to store your data.
I am in the process of writing software for an STM32F4. The STM32 needs to pull in a string via a UART. This string is variable in length and comes in from a sensor every second. The string is stored in a fixed buffer, so the buffer content changes continuously.
The incoming string looks like this: "A12941;P2507;T2150;C21;E0;"
The settings of the UART:
Baud Rate: 19200
Word lengt: 8Bits
Parity: None
Stop Bids: 1
Over sampling: 16 Samples
Global interrupt: Enabled
No DMA settings
Part of the used code in the main.c function:
uint8_t UART3_rxBuffer[25];
void HAL_UART_RxCpltCallback(UART_HandleTypeDef *huart)
{
HAL_UART_Receive_IT(&huart3, UART3_rxBuffer, 25); //restart interrupt reception mode
int main(void)
{
HAL_UART_Receive_IT (&huart3, UART3_rxBuffer,25);
}
while (1)
{
}
}
Part of the code in stm32f4xx_it.c
void USART3_IRQHandler(void)
{
/* USER CODE BEGIN USART3_IRQn 0 */
/* USER CODE END USART3_IRQn 0 */
HAL_UART_IRQHandler(&huart3);
/* USER CODE BEGIN USART3_IRQn 1 */
/* USER CODE END USART3_IRQn 1 */
}
It does work to fill the buffer with the variable strings in this way, but because the buffer is constantly being replenished, it is difficult to extract a beginning and an end of the string. For example, the buffer might look like this:
[0]'E' [1]'0' [2]'/n' [3]'A' [4]'1' [5]'2' [6]'9' [7]'4' [8]'1' [9]';' [10]'P' etc....
But I'd like to have a buffer that starts on 'A'.
My question is, how can I process incoming strings on the uart correctly so that I only have the string "A12941;P2507;T2150;C21;E0;"?
Thanks in advance!!
I can see three possibilities:
Do all of your processing in the interrupt. When you get to the end of a variable-length message then do everything that you need to do with the information and then change the location variable to restart filling the buffer from the start.
Use (at least) two buffers in parallel. When you detect the end of the variable-length message in interrupt context then start filling a different buffer from position zero and signal to main context that previous buffer is ready for processing.
Use two buffers in series. Let the interrupt fill a ring buffer in a circular way that takes no notice of when a message ends. In main context scan from the end of the previous message to see if you have a whole message yet. If you do, then copy it out into another buffer in a way that makes it start at the start of the buffer. Record where it finished in the ring-buffer for next time, and then do your processing on the linear buffer.
Option 1 is only suitable if you can do all of your processing in less than the time it takes the transmitter to send the next byte or two. The other two options use a bit more memory and are a bit more complicated to implement. Option 3 could be implemented with circular mode DMA as long as you poll for new messages frequently enough, which avoids the need for interrupts. Option 2 allows to queue up multiple messages if your main context might not poll frequently enough.
I would like to share a sample code related to your issue. However it is not what you are exactly looking for. You can edit this code snippet as you wish. If i am not wrong you can also edit it according to option 3.
void HAL_UART_RxCpltCallback(UART_HandleTypeDef *huart)
{
if (huart->Instance == USART2) {
HAL_UART_Receive_IT(&huart2,&rData,1);
rxBuffer[pos++] = rData;
if (rData == '\n') {
pos = 0;
}
}
Before start, in the main function, before while loop you should enable interrupt for one byte using "HAL_UART_Receive_IT(&huart2,&rData,1);". If your incoming data has limiter like '\n', so you can save whole data which may have different length for each frame.
If you want data frame start with some specific character, then you can wait to save data until you get this character. In this case you can edit this code by changing '\n' as your character, and after you get that character, you should start to save following data to inside the buffer.
I have a single-threaded program that runs on a WEC2013 device. Since the device has no display I use a Telnet connection to the device.
I want to show some progress indication. For that purpose I added a printf statement:
void DoTimeConsumingCalculation()
{
for (auto step = 0; step < 100; ++step)
{
// calculate, takes about 10 seconds
CrunchNumbers();
// keep the user happy
printf(".");
}
printf("\n");
}
Instead of issuing dots during the calculation this results in a complete line that is sent to the client when the \n is sent.
I experiemented with fflush(stdout); and setvbuf(0, _IONBF,0); without any effect. Even fprintf(stderr, '.'); gives the same result.
But when I use printf(".."); I get two dots immediately. But this is not the output I need.
How can I convince the C-runtime library to send each single character?
So I'm trying to program a game using flash, and it's my very first time and I can't get something to work.
In the game, a ball will float across the screen and if you click on it you get 2 points. Except when I test it, the first time I click on the ball I get the letters 'eoceeeo' and if I click the ball again I get the letters 'eeoS'. The dynamic text is on a layer with the first frame having the AS of
var _root.score = 0;
gameScore.text = _root.score;
The dynamic text has a varible of _root.score and a name of gameScore
The floating ball has the AS of
on(release) { _root.score+=2; _root.gameScore.text = _root.score; }
If you click on your gameScore dynamic text field, you can scroll down to its Variable property and set that as _root.score. That way, you do not have to call gameScore.text = _root.score every time the score changes - it will simply update automatically.
Also, if you remove the var from in front of _root.score = 0, it will be easier for ActionScript to handle. Perhaps, you are casting the score variable as an integer, and the dynamic text field is having trouble displaying it as a string of characters. This can also be solved with String(_root.score) and score.toString().
That should make your code a bit less complex, and help for you to identity your random letters problem, which can't be solved specifically with the information you have here. Hope that helps!