© MCS Electronics, 1995-2007

Config Com1 = Dummy , Synchrone = 0 , Parity = None , Stopbits = 1 , Databits = 8 , Clockpol = 0

Config Com2 = Dummy , Synchrone = 0 , Parity = None , Stopbits = 1 , Databits = 8 , Clockpol = 0

'setup to use a serial output buffer 'and reserve 20 bytes for the buffer Config Serialout = Buffered , Size = 254

'It is important since UDRE interrupt is used that you enable the interrupts

Enable Interrupts Print "Hello world" Print "test1"

Do Wait 1

'notice that using the UDRE interrupt will slown down execution of waiting loops like waitms

Print "test"

Loop

End

CONFIG SERIALOUT1

Action

Configures the second hardware UART to use a buffer for output

Syntax

CONFIG SERIALOUT1 = BUFFERED , SIZE = size

Remarks

The following internal variables will be used when you use CONFIG SERIALOUT

_RS_HEAD_PTRW1 , byte that stores the head of the buffer _RS_TAIL_PTRW1 , byte that stores the tail of the buffer

_RS232OUTBUF1, array of bytes for the ring buffer that stores the printed data. _RS_BUFCOUNTW1, a byte that holds the number of bytes in the buffer.

Serial buffered output can be used when you use a low baud rate. It would take relatively much time to print all data without a buffer. When you use a buffer, the data is printed on the background when the micro UART byte buffer is empty. It will get a byte from the buffer then and transmit it.

As with any buffer you have, you must make sure that it is emptied at one moment in time. You can not keep filling it as it will become full. When you do not empty it, you will have the same situation as without a buffer !!! When the roof is leaking and you put a bucket on the floor and in the morning you empty it, it will work. But when you will go away for a day, the bucket will overflow and the result is that the floor is still wet.

Another important consideration is data loss. When you print a long string of 100 bytes, and there is only room in the buffer for 80 bytes, there is still a wait evolved since after 80 bytes, the code will wait for the buffer to become empty. When the buffer is empty it will continue to print the data. The advantage is that you do not loose any data, the

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'notice that using the UDRE interrupt will slown down execution of waiting loops like waitms

Print #1 , "test"

Loop

End

Close #1

CONFIG SINGLE

Action

Instruct the compiler to use an alternative conversion routine for representation of a single.

Syntax

CONFIG SINGLE = SCIENTIFIC , DIGITS = value

Remarks

When a conversion is performed from numeric single variable, to a string, for example when you PRINT a single, or when you use the STR() function to convert a single into a string, a special conversion routine is used that will convert into human readable output. You will get an output of digits and a decimal point.

This is well suited for showing the value on an LCD display. But there is a downside also. The routine is limited in the way that it can not shown very big or very small numbers correct.

The CONFIG SINGLE will instruct the compiler to use a special version of the conversion routine. This version will use scientific notation such as : 12e3.

You can specify how many digits you want to be included after the decimal point.

See also

NONE

ASM

Uses single.lbx library

Example

'----------------------------------------------------------------

' demonstation of scientific , single output '----------------------------------------------------------------

$regfile= "m88def.dat" $crystal= 8000000

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$baud = 19200

'you can view the difference by compiling and simulating this sample with the 'line below remarked and active

Config Single = Scientific,Digits= 7

Dim S As Single

S = 1

Do

S= S / 10

Print S

Loop

CONFIG SPI

Action

Configures the SPI related statements.

Syntax for software SPI

CONFIG SPI = SOFT, DIN = PIN, DOUT = PIN , SS = PIN|NONE, CLOCK = PIN

Syntax for hardware SPI

CONFIG SPI = HARD, INTERRUPT=ON|OFF, DATA ORDER = LSB|MSB , MASTER = YES|NO , POLARITY = HIGH|LOW , PHASE = 0|1, CLOCKRATE = 4|16|64|128 , NOSS=1|0

Remarks

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The default setting for hardware SPI when set from the Compiler, Options, SPI menu is MSB first, POLARITY = HIGH, MASTER = YES, PHASE = 0, CLOCKRATE = 4

When you use CONFIG SPI = HARD alone without the other parameters, the SPI will only be enabled. It will work in slave mode then with CPOL =0 and CPH=0.

In hardware mode the SPIINIT statement will set the SPI pins to : sbi DDRB,7 ; SCK output

cbi DDRB,6 ; MISO input sbi DDRB,5 ; MOSI output

In softmode the SPIINIT statement will set the SPI pins for example to : sbi PORTB,5 ;set latch bit hi (inactive)SS

sbi DDRB,5 ;make it an output SS cbi PORTB,4 ;set clk line lo

sbi DDRB,4 ;make it an output cbi PORTB,6 ;set data-out lo MOSI

sbi DDRB,6 ;make it an output MOSI cbi DDRB,7 ;MISO input

Ret

When you want to address multiple slaves with the software SPI you need multiple pins to select/activate the slave chip. Specify NONE for SS in that case. This also means that before every SPI command you need to set the logic level to 0 to address the chip and after the SPI command you need to set it back to a logic high level.

The hardware SPI also has this option. The NOSS parameter with a value of 1, wil not set the SS line to logic 0 when the SPI operation begins. You need to set SS or any other pin of your choice to a logic 0 yourself. After the SPI command(s) are used you need to set it back to a logic 1 to deselect the slave chip.

All SPI routines are SPI-master routines. Example 2 below demonstrates how to create a soft SPI slave. In the samples directory you will also find a SPI hardware master and SPI hardware slave sample.

See also

SPIIN , SPIOUT , SPIINIT , SPI , SPIMOVE

Example

Config SPI = SOFT, DIN = PINB.0 , DOUT = PORTB.1, SS = PORTB.2, CLOCK = PORTB.3

Dim var As Byte

SPIINIT 'Init SPI state and pins. SPIOUT var , 1 'send 1 byte

CONFIG SERVOS

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