Manchester Code Library

The mikroPascal PRO for ARM provides a library for handling Manchester coded signals. The Manchester code is a code in which data and clock signals are combined to form a single self-synchronizing data stream; each encoded bit contains a transition at the midpoint of a bit period, the direction of transition determines whether the bit is 0 or 1; the second half is the true bit value and the first half is the complement of the true bit value (as shown in the figure below).

Manchester signal format

  Important :

External dependencies of Manchester Code Library

Stellaris

The following variables must be defined in all projects using Manchester Code Library: Description: Example:
var MANRXPIN : sbit; sfr; external; Receive line. var MANRXPIN : sbit at GPIO_PORTE_DATA.B0;
var MANTXPIN : sbit; sfr; external; Transmit line. var MANTXPIN : sbit at GPIO_PORTE_DATA.B1;
var MANRXPIN_Direction : sbit; sfr; external; Direction of the Receive pin. var MANRXPIN_Direction : sbit at GPIO_PORTE_DIR.B0;
var MANTXPIN_Direction : sbit; sfr; external; Direction of the Transmit pin. var MANTXPIN_Direction : sbit at GPIO_PORTE_DIR.B1;

MSP432

The following variables must be defined in all projects using Manchester Code Library: Description: Example:
var MANRXPIN : sbit; sfr; external; Receive line. var MANRXPIN : sbit at DIO_P6IN.B0;
var MANTXPIN : sbit; sfr; external; Transmit line. var MANTXPIN : sbit at DIO_P6OUT.B1;
var MANRXPIN_Direction : sbit; sfr; external; Direction of the Receive pin. var MANRXPIN_Direction : sbit at DIO_P6DIR.B0;
var MANTXPIN_Direction : sbit; sfr; external; Direction of the Transmit pin. var MANTXPIN_Direction : sbit at DIO_P6DIR.B1;

STM32

The following variables must be defined in all projects using Manchester Code Library: Description: Example:
var MANRXPIN : sbit; sfr; external; Receive line. var MANRXPIN : sbit at GPIOE_IDR.B8;
var MANTXPIN : sbit; sfr; external; Transmit line. var MANTXPIN : sbit at GPIOE_ODR.B9;

CEC1x02

The following variables must be defined in all projects using Manchester Code Library: Description: Example:
var MANRXPIN : sbit; sfr; external; Receive line. var MANRXPIN : sbit at GPIO_INPUT_PIN_023_bit;
var MANTXPIN : sbit; sfr; external; Transmit line. var MANTXPIN : sbit at GPIO_OUTPUT_PIN_023_bit;

Library Routines

The following routines are for the internal use by compiler only:

Man_Receive_Init

Prototype

function Man_Receive_Init() : word;
Description

The function configures Receiver pin. After that, the function performs synchronization procedure in order to retrieve baud rate out of the incoming signal.
Parameters

None.
Returns

  • 0 - if initialization and synchronization were successful.
  • 1 - upon unsuccessful synchronization.
  • 255 - upon user abort.
Requires

External dependencies of the library from the top of the page must be defined before using this function.
Example

Stellaris

// Manchester module connections
var MANRXPIN : sbit at GPIO_PORTE_DATA.B0;
    MANRXPIN_Direction : sbit at GPIO_PORTE_DIR.B0;
    MANTXPIN : sbit at GPIO_PORTE_DATA.B1;
    MANTXPIN_Direction : sbit at GPIO_PORTE_DIR.B1;
// End Manchester module connections
...
Man_Receive_Init();

MSP432

// Manchester module connections
var MANRXPIN : sbit at DIO_P6IN.B0;
    MANRXPIN_Direction : sbit at DIO_P6DIR.B0;
    MANTXPIN : sbit at DIO_P6OUT.B1;
    MANTXPIN_Direction : sbit at DIO_P6DIR.B1;
// End Manchester module connections
...
Man_Receive_Init();

STM32

// Manchester module connections
var MANRXPIN: sbit at GPIOE_IDR.B8;
var MANTXPIN: sbit at GPIOE_ODR.B9;
// End Manchester module connections
...
Man_Receive_Init();

CEC1x02

// Manchester module connections
var MANRXPIN: sbit at GPIO_INPUT_PIN_023_bit;
var MANTXPIN: sbit at GPIO_OUTPUT_PIN_023_bit;
// End Manchester module connections
...
Man_Receive_Init();
Notes

In case of multiple persistent errors on reception, the user should call this routine once again or Man_Synchro routine to enable synchronization.

Man_Receive

Prototype

function Man_Receive(var error : word) : byte;
Description

The function extracts one byte from incoming signal.
Parameters
  • error: error flag. If signal format does not match the expected, the error flag will be set to non-zero.
Returns

A byte read from the incoming signal.
Requires

To use this function, the user must prepare the MCU for receiving. See Man_Receive_Init routines.
Example 
var data_, error : word;
...
error := 0;
data_ := 0;
data_ := Man_Receive(error);
if (error <> 0) then
begin 
	// error handling 
end;
Notes

None.

Man_Send_Init

Prototype

procedure Man_Send_Init();
Description

The function configures Transmitter pin.
Parameters

None.
Returns

Nothing.
Requires

External dependencies of the library from the top of the page must be defined before using this function.
Example

Stellaris

// Manchester module connections
var MANRXPIN : sbit at GPIO_PORTE_DATA.B0;
    MANRXPIN_Direction : sbit at GPIO_PORTE_DIR.B0;
    MANTXPIN : sbit at GPIO_PORTE_DATA.B1;
    MANTXPIN_Direction : sbit at GPIO_PORTE_DIR.B1;
// End Manchester module connections
...
Man_Send_Init();

MSP432

// Manchester module connections
var MANRXPIN : sbit at DIO_P6IN.B0;
    MANRXPIN_Direction : sbit at DIO_P6DIR.B0;
    MANTXPIN : sbit at DIO_P6OUT.B1;
    MANTXPIN_Direction : sbit at DIO_P6DIR.B1;
// End Manchester module connections
...
Man_Send_Init();

STM32

// Manchester module connections
var MANRXPIN: sbit at GPIOE_IDR.B8;
var MANTXPIN: sbit at GPIOE_ODR.B9;
// End Manchester module connections
...
Man_Send_Init();

CEC1x02

// Manchester module connections
var MANRXPIN: sbit at GPIO_INPUT_PIN_023_bit;
var MANTXPIN: sbit at GPIO_OUTPUT_PIN_023_bit;
// End Manchester module connections
...
Man_Send_Init();
Notes

None.

Man_Send

Prototype

procedure Man_Send(tr_data : byte);
Description

Sends one byte.
Parameters
  • tr_data: data to be sent
Returns

Nothing.
Requires

To use this function, the user must prepare the MCU for sending. See Man_Send_Init routine.
Example 
var msg : byte;
...
Man_Send(msg);
Notes

Baud rate used is 500 bps.

Man_Synchro

Prototype

function Man_Synchro(): word;
Description

Measures half of the manchester bit length with 10us resolution.
Parameters

None.
Returns
  • 0 - if synchronization was not successful.
  • Half of the manchester bit length, given in multiples of 10us - upon successful synchronization.
Requires

To use this function, you must first prepare the MCU for receiving. See Man_Receive_Init.
Example 
var man__half_bit_len : word;
...
man__half_bit_len := Man_Synchro();
Notes

None.

Man_Break

Prototype

procedure Man_Break();
Description

Man_Receive is blocking routine and it can block the program flow. Call this routine from interrupt to unblock the program execution. This mechanism is similar to WDT.
Parameters

None.
Returns

Nothing.
Requires

Nothing.
Example 

          		
        

       
        

          Notes
          
            
Interrupts should be disabled before using Manchester routines again (see note at the top of this page).