lib-lpc2k-planning — Mailing List for the Planning Stage of lib-lpc2k

[lib-lpc2k-planning] Register Definitions

[Shahzeb I. <sh...@gm...>]

Hi,

I was thinking over how registers should be defined in the library. Regular
registers can be define simply as:

#define LPC_CAN_AFMR_REG                (*(volatile DWORD *)0xE003C000)

But a lot of LPC peripherals have multiple modules, like UART, I2C, Timer
etc. For registers like these, I normally define structures. A library
function can then declare a pointer to the strcuture and assign the proper
address to it based on which module is being accessed, examples are given
below for FIO and UART registers. One advantage of this approach is the
re-usability of library functions in such situations. These examples are
taken from a HAL I've previously implemented, hence the use of "DWORD"
instead of "uint32_t".

Suggestions? Comments?

-------------------------------------------------------------------------------------------

typedef volatile struct
{
     DWORD regIODIR;        // FIO pin direction control register (base
address + 0x00)
     DWORD dwUnused1;    // Unused address...
     DWORD dwUnused2;    // Unused address...
     DWORD dwUnused3;    // Unused address...
     DWORD regIOMASK;    // FIO pin mask register (base address + 0x10)
     DWORD regIOPIN;        // FIO pin value register (base address + 0x14)
     DWORD regIOSET;       // FPIO pin set register (base address + 0x18)
     DWORD regIOCLR;       // FIO pin set register (base address + 0x1C)
}
tsLPC_FIO_REG;

-------------------------------------------------------------------------------------------

typedef volatile struct
{
     union tuLPC_REG_UART_MUX_0
     {
          DWORD regRBR;                 // UART receive buffer register
(base address + 0x00), read only access (DLAB = 0)
          DWORD regTHR;                 // UART transmit holding register
(base address + 0x00), write only access (DLAB = 0)
          DWORD regDLL;                 // UART divisor latch LSB register
(base address + 0x00), read/write access (DLAB = 1)
     }
     uMux0;

     union tuLPC_REG_UART_MUX_1
     {
          DWORD regDLM;                 // UART divisor latch MSB register
(base address + 0x04), read/write access (DLAB = 1)
          DWORD regIER;                 // UART interrupt enable register
(base address + 0x04), read/write access (DLAB = 0)
     }
     uMux1;

     union tuLPC_REG_UART_MUX_2
     {
          DWORD regIIR;                 // UART interrupt identification
register (base address + 0x08), read only access
          DWORD regFCR;                 // UART FIFO control register (base
address + 0x08), write only access
     }
     uMux2;

     DWORD regLCR;                      // UART line control register (base
address + 0x0C)
     DWORD regMCR;                      // UART modem control register (base
address + 0x10)
     DWORD regLSR;                      // UART line status register (base
address + 0x14)
     DWORD regMSR;                      // UART modem status register (base
address + 0x18)
     DWORD regSCR;                      // UART scratch pad register (base
address + 0x1C)
     DWORD regACR;                      // UART auto-baud control register
(base address + 0x20)
     DWORD dwUnused1;                   // Unused address...
     DWORD regFDR;                      // UART fractional divider register
(base address + 0x28)
     DWORD dwUnused2;                   // Unused address...
     DWORD regTER;                      // UART TX enable register
}
tsLPC_UART_REG;

-------------------------------------------------------------------------------------------

-- 
"Keep me away from the wisdom which does not cry, the philosophy which does
not laugh and the greatness which does not bow before children."
---Khalil Gibran

[lib-lpc2k-planning] Test message...

[Shahzeb I. <sh...@gm...>]

This a test message, please reply if you receive this message, you'll have
to subscribe using your original email address if you wish to
post on the list. I initially subscribed all members using their sourceforge
forwarding addresses.
-- 
"Keep me away from the wisdom which does not cry, the philosophy which does
not laugh and the greatness which does not bow before children."
---Khalil Gibran