Posted on February 23, 2015 at 11:14
I don't share the UART class, although it is derived from a more generic Stream class, which allows me to putch() getch() and gotch() in a reasonably generic manner. The FIFO class is a reasonably generic fifo. Please forgive my coding style, which can at times be a bit terse 🙂
class
Fifo_C
{
private
:
u8 *pBuffer;
// Pointer to the data storage buffer
u16 BufferSize;
// The length of the data buffer
u16 PutIdx;
// Destination for putch
u16 GetIdx;
// Source for getch
void
IncGetter(
void
)
{ GetIdx++;
if
(GetIdx >= BufferSize) GetIdx = 0; }
public
:
u16 Used;
u16 MaxUsed;
void
Reset(
void
)
{ MaxUsed = Used = PutIdx = GetIdx = 0; }
void
SetBuffer(u8 *pData, u16 DataLength)
{ pBuffer = pData; BufferSize = DataLength; Reset(); }
volatile
bool
gotch(
void
)
// Anything in the FIFO?
{
return
PutIdx != GetIdx; }
u8 getch(
void
)
{
if
(! gotch())
return
0; u8 ch = pBuffer[GetIdx];
IncGetter();
return
ch; }
u8 peek(
void
)
{
return
pBuffer[GetIdx]; }
void
putch(u8 c)
{ u16 tmpGetIdx = GetIdx; pBuffer[PutIdx] = c;
PutIdx++;
if
(PutIdx >= BufferSize) PutIdx = 0;
if
(PutIdx == tmpGetIdx)
printf
(
'' FIFO Overflow %p ''
,
this
);
Used = Length(); MaxUsed = max(MaxUsed, Used); }
volatile
u16 Length(
void
)
// The current number of items in the fifo
{
if
(PutIdx >= GetIdx)
return
PutIdx - GetIdx;
return
BufferSize + PutIdx - GetIdx; }
u16 Spare(
void
)
// The amount of space left in the fifo.
{
return
BufferSize - Length(); }
};
To use it, give it some memory:
u8 FifoMem[300];
Fifo_C MyFifo;
void
OnStartup(
void
)
{
// Apply memory buffer to fifo
MyFifo.SetBuffer(FifoMem,
sizeof
(FifoMem));
// Use the fifo
}
