Respected Sir/Madam, we are working on a project which has 56f805 DSP on the EVM kit. we're new to embedded field. we have a few queries which need to be cleared to start our project. kindly help us by doing the need. The queries are as follows: 1. A basic sample program to use ADC, along with the connections specified. 2. how to access the result registers to watch the digital outputs? 3. Detailed working of ADC. 4. Whatz the meaning of 8.5 ADC clock cycles, 26.5 ADC clock cycles? 5. differences b/w sequential, simultaneous modes and single ended, differential i/ps and how are these related to each other. 6. How to use ADC channel list registers? we have the following pdf files - 56f80x Users Manual, Data sheets, EVMUM But we are finding it difficult to find answers to these questions. plz help us out as we are not able to proceed further in our project. we will be grateful to u. Thanking U, Regards, Sowmya and Devika. |
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ADC usage
Started by ●November 28, 2004
Reply by ●November 30, 20042004-11-30
Dear Sowmya and Devika,
the better place to look for informations on ADC is the user manual:
DSP80F801-7UM;
You have there answers to all your questions.
For instance, a single conversion takes 8.5 of the ADC clock cycles; the
following conversion will take only 6 cycles, yielding 14.5 cycles for the 2
conversions (or the 4 conversions if the 2 channels of the ADC are working).
Thus 4 conversions (or 8 ) will take 26.5 cycles).
This can work, but has many instructions you will find useless.
// Initialisation ADC
move #$0004,x:$0E81 move #$0000,x:$0E82 move #$0010,x:$0E83 // 000 (AN0) and 001 (AN1) slots 0 and 1 move #$0000,x:$0E84 // for converting only AN0 and AN1 move #$00FC,x:$0E85 // inhibition other ch than 0 and 1 move #$0000,x:$0E91 // limit inf: 0 for AN0 move #$0000,x:$0E92 // limit inf: 0 for AN1 move #$7FF8,x:$0E99 // limit sup: 0 for AN0 move #$7FF8,x:$0E9A // limit sup: 0 for AN1 move #$0000,x:$0EA1 // offset 0 for AN0 move #$0000,x:$0EA2 // offset 0 for AN1 // Read ADC move #$3002,x:$0E80 // init a cv if not done cv: move x:$0E86,x0 // raed stat register bftsth #0001,x0
bcc cv // end conversion? no wait at cv move x:$0E89,x0 // yes: read ADC 0 asr x0 // remove the 3 LSB (they means nothing) asr x0 asr x0 Regards. sowmya_gk <s...@vsnl.net> wrote:
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Reply by ●November 30, 20042004-11-30
hi!i am also newbie in dsp(i have 8323 dev. board but their ADC is similar to yours...) the number of replies in this group not much for a long time...i'll try to answer as i can... in the peripheral user manual you can find enough information for questions 3,4 and 5... single ended means adc will convert the voltage on the ADC input pin(this is normal operation you know)... in diferantial mode adc will convert the difference betveen 2 input.. there is two adc mudule and in simulteneous mode both of them works in same time... in sequential mode you can use just 1 adc module acording to adc pin that you use.... firsly you use metrowerk code warrior... and processor expert -PE- embedden inside of it... you can use PE to initalize your ADC... and looking at to generated code by PE you can understant how to acces ADC registers... there is two way to acces peripherel register...you can use PE PESL functions(more effective) and you can use c functions like getREG16();..for example to acces result register use getReg16(ADCA_ADRSLT0); for the register names look at the inside of #include "IO_Map.h"... in 56f8323 ADC clock 5MHz..this information is in peripheral user manuel...so 8.5 adc clock cycle 1,7 us... isa --- sowmya_gk <> wrote: > > Respected Sir/Madam, > we are working on a project which has 56f805 DSP on > the EVM > kit. we're new to embedded field. > we have a few queries which need to be cleared to > start our project. > kindly help us by doing the need. > The queries are as follows: > 1. A basic sample program to use ADC, along with the > connections > specified. > 2. how to access the result registers to watch the > digital outputs? > 3. Detailed working of ADC. > 4. Whatz the meaning of 8.5 ADC clock cycles, 26.5 > ADC clock cycles? > 5. differences b/w sequential, simultaneous modes > and single ended, > differential i/ps and how are these related to each > other. > 6. How to use ADC channel list registers? > > we have the following pdf files - 56f80x Users > Manual, Data > sheets, EVMUM > But we are finding it difficult to find answers to > these questions. > plz help us out as we are not able to proceed > further in our project. > we will be grateful to u. > Thanking U, > > Regards, > Sowmya and Devika. > > __________________________________ |