Hi,
I am having trouble to configure the ADC to work with the DMA on the SM470R1B1M. The ADC is configured in buffer mode, FIFO size 64 words. The ADCLK = 30MHz.
To get 500KHz as sampling frequency, the SW is set to 40.
ADC configuration:
ADCR1 |= PS_1; // ADCLK prescaler = 1
ADSAMPEV |= SEN; // ADCSAMP1 controls SW
ADSAMP1 = 38; // SW = 38+2
ADBCR1 = 0x0000; // BNDA = BNDB = 0
ADBCR1 |= BUF_EN; // Buffer mode enabled
ADBCR2 = 0x2; // BNDEND = 010 => 64 words (the MAX availabled on the SM470R1B1M)
ADBCR3 |= G1_DMA_EN; // Group 1 DMA enabled
ADCR2 |= G1_MODE; // Continuous Conversion
// TMS470R1x Multi-Buffered Analog-to-Digital Converter (MibADC) Reference
// Guide, pag.65
// Analog-to-digital converter enable.
// When this bit is cleared to 0, the ADC state machine is
// in idle state. While the ADC EN bit is cleared, the inputselect
// registers (ADEISR, ADISR1, and ADISR2), and
// the status register (ADSR) are held at their reset values.
// When ADC EN = 1, the ADC state machine is released,
// which allows normal ADC operation to start.
ADCR1 |= ADC_EN; // Enable ADC
// Pin ADIN6
ADISR1 = (1<<6); // Convert group 1 = channel 6
------------------------------------------------------------------------
DMA configuration:
// DMA transfer is done through Channel 4 (ADC G1/MibADCDMA1) using Control
// Packet 0
// Control Packet 0
// Interrupt enabled = 1
// Transaction Access Size = 16 bits
// Destination Increment = 1
// Source Increment = 0
// Destination Module = memory select 2
// Source Module = peripheral
DMAC00 = 0x0000A84E;
DMASA00 = (uint32)&ADBUF1; // ADC Group 1 FIFO buffer
DMADA00 = dest;
DMATC00 = 64; // The number of DMA transactions to be completed.
// Channel 4
// Interrupt level = 0
// Suspend enable = 0
// Request enable = 1
DMACC0 = 0x00020000;
// Control Packet 0 is updated and will be used for transfer.
DMACPS = 0x00000001;
DMAGC = 0x00000000;
// DMA halt disabled
// DMA stop disabled
DMAGD = 0x00000000;
DMACCP1 = 0x40; // DMAEN4 set to 1
The DMA interrupt (CIM_DMA0) never goes OFF, the data is not read out into the application buffer. When I pause the debugger the registers show that the ADC overruns:
ADBUFST:
G1_EMPTY = 0
G1_OVR_FLAG = 1
G1_INT_FALG = 1
ADSR:
G1_END = 1
G1_BUSY = 1
Is there anything obviously missed? or wrong?
Thanks,
Giuseppe
