Allows access to external RAM with bank-switching. More...

Files
file	xmem.h
	XMEM API Header.

file	xmem.c
	XMEM API Implementation.

Data Structures
struct	MallocState
	All Malloc related State. More...

Macros
#define	MEMSWITCH(x) uint8_t oldMemBank=xmemGetBank();if(oldMemBank!=x)xmemSetBank(x);
	Switch the bank, if needed. More...

#define	MEMSWITCHBACK(x) if(oldMemBank!=x)xmemSetBank(oldMemBank);
	Switch back to the last bank, if needed. More...

#define	MEMBANKS 8
	Available Memory Banks. More...

#define	BANK_GENERIC 0
	Generic Memory Bank. More...

Functions
void	xmemInit (void)
	Initialize the External Memory Interface. More...

void	xmemSetBank (uint8_t bank)
	Switch the active memory bank. More...

uint8_t	xmemGetBank (void)
	Get the current memory bank. More...

void	saveState (uint8_t bank)
	Save the current malloc state. More...

void	restoreState (uint8_t bank)
	Restore the malloc state. More...

Variables
MallocState	states [MEMBANKS]
	MallocState for all Memory Banks. More...

uint8_t	currentBank
	Current active Memory Bank. More...

MallocState	states [MEMBANKS]
	MallocState for all Memory Banks. More...

uint8_t	currentBank = 0
	Current active Memory Bank. More...

void *	__brkval
	Internal Malloc Heap-End Pointer. More...

void *	__flp
	Internal Malloc Free List Pointer (State) More...

Detailed Description

Allows access to external RAM with bank-switching.

Macro Definition Documentation

#define BANK_GENERIC 0

Generic Memory Bank.

Definition at line 55 of file xmem.h.

Referenced by addMenuCommand(), addTask(), removeTask(), tasks(), tasksRegistered(), uartMenuPrintHelp(), and uartMenuTask().

#define MEMBANKS 8

Available Memory Banks.

Examples:: hardwareTest.c.

Definition at line 54 of file xmem.h.

Referenced by xmemInit(), and xmemSetBank().

#define MEMSWITCH ( x ) uint8_t oldMemBank=xmemGetBank();if(oldMemBank!=x)xmemSetBank(x);

Switch the bank, if needed.

Stores the old bank in a variable oldMemBank.

Parameters

x New Bank

Definition at line 47 of file xmem.h.

Referenced by addTask(), removeTask(), tasks(), and tasksRegistered().

#define MEMSWITCHBACK ( x ) if(oldMemBank!=x)xmemSetBank(oldMemBank);

Switch back to the last bank, if needed.

Parameters

x	New (current) Bank

Definition at line 52 of file xmem.h.

Referenced by addTask(), removeTask(), tasks(), and tasksRegistered().

Function Documentation

void restoreState ( uint8_t bank )

Restore the malloc state.

Parameters

bank	Location of state to load.

Definition at line 65 of file xmem.c.

References __brkval, __flp, MallocState::end, MallocState::fl, MallocState::start, and MallocState::val.

Referenced by xmemSetBank().

                                 {
     __malloc_heap_start = states[bank].start;
     __malloc_heap_end = states[bank].end;
     __brkval = states[bank].val;
     __flp = states[bank].fl;
 }

void saveState ( uint8_t bank )

Save the current malloc state.

Parameters

bank	Current Bank Number

Definition at line 55 of file xmem.c.

References __brkval, __flp, MallocState::end, MallocState::fl, MallocState::start, and MallocState::val.

Referenced by xmemInit(), and xmemSetBank().

                              {
     states[bank].start = __malloc_heap_start;
     states[bank].end = __malloc_heap_end;
     states[bank].val = __brkval;
     states[bank].fl = __flp;
 }

uint8_t xmemGetBank ( void )

Get the current memory bank.

Returns: Current Memory Bank.

Examples:: hardwareTest.c.

Definition at line 105 of file xmem.c.

References currentBank.

Referenced by addMenuCommand(), uartMenuPrintHelp(), and uartMenuTask().

                           {
     return currentBank;
 }

void xmemInit ( void )

Initialize the External Memory Interface.

Definition at line 72 of file xmem.c.

References BANK0DDR, BANK0PIN, BANK0PORT, BANK1DDR, BANK1PIN, BANK1PORT, BANK2DDR, BANK2PIN, BANK2PORT, MEMBANKS, and saveState().

Referenced by xyInit().

                     {
     BANK0DDR |= (1 << BANK0PIN);
     BANK1DDR |= (1 << BANK1PIN);
     BANK2DDR |= (1 << BANK2PIN);
     BANK0PORT &= ~(1 << BANK0PIN);
     BANK1PORT &= ~(1 << BANK1PIN);
     BANK2PORT &= ~(1 << BANK2PIN);
 
     XMCRB = 0; // Use full address space
     XMCRA = (1 << SRW11) | (1 << SRW10); // 3 Wait cycles
     XMCRA |= (1 << SRE); // Enable XMEM
 
     for (uint8_t i = 0; i < MEMBANKS; i++) {
         saveState(i);
     }
 }

void xmemSetBank ( uint8_t bank )

Switch the active memory bank.

Parameters

bank	New Memory Bank

Examples:: hardwareTest.c.

Definition at line 89 of file xmem.c.

References BANK0PIN, BANK0PORT, BANK1PIN, BANK1PORT, BANK2PIN, BANK2PORT, currentBank, MEMBANKS, restoreState(), and saveState().

Referenced by addMenuCommand(), uartMenuPrintHelp(), and uartMenuTask().

                                {
     if (bank < MEMBANKS) {
         saveState(currentBank);
 
         BANK0PORT &= ~(1 << BANK0PIN);
         BANK1PORT &= ~(1 << BANK1PIN);
         BANK2PORT &= ~(1 << BANK2PIN);
         BANK0PORT |= ((bank & 0x01) << BANK0PIN);
         BANK1PORT |= (((bank & 0x02) >> 1) << BANK1PIN);
         BANK2PORT |= (((bank & 0x04) >> 2) << BANK2PIN);
 
         currentBank = bank;
         restoreState(bank);
     }
 }