Hi all, I'm trying to use A/D module in interrupts with predefined acquisition time. (PIC 18F2550 datasheet, rev DS39632E pp.267)
Please let me know if my assumption bellow is correct. DATASHEET: "Acquisition time may be set with the ACQT2:ACQT0 bits (ADCON2<5:3>) which provide a range of 2 to 20 TAD. When the GO/DONE bit is set, the A/D module continues to sample the input for the selected acquisition time, then automatically begins a conversion. Since the acquisition time is programmed, there may be no need to wait for an acquisition time between selecting a channel and setting the GO/DONE bit." For a 48MHz clock, the recommended AD conversion clock is 64Tosc ( 64/Fosc), meaning 1.33uS. The minimum required AD acquisition time is TACQ=2.45uS. The minimum acquisition time which must be set (for one acquisition) seems to be at least 2TAD. Meaning ADCON2_ ACQT = 0b001 and ADCON2_ADCS = 0b110 DATASHEET: "For correct A/D conversions, the A/D conversion clock (TAD) must be as short as possible but greater than the minimum TAD (see parameter 130 in Table 28-29 for more information)". Data from Table28-29: TAQ min= 1.4uS (parameter 130) TAD min = 0.8uS TCNV (conversion time without TACQ) = 11TAD How do you understand the info above ? thank you, Vasile -- You received this message because you are subscribed to the Google Groups "jallib" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/jallib?hl=en. For more options, visit https://groups.google.com/groups/opt_out.
