;;;; -*- Mode: LISP; Syntax: ANSI-Common-Lisp; Base: 10 -*- ;;;; ************************************************************************* ;;;; FILE IDENTIFICATION ;;;; ;;;; Name: cluck.lisp ;;;; Purpose: Common Lisp uControler Clock Calculator ;;;; Programmer: Kevin M. Rosenberg ;;;; Date Started: March 2007 ;;;; ;;;; $Id$ ;;;; ;;;; Copyright (c) 2007 Kevin M. Rosenberg ;;;; ;;;; Redistribution and use in source and binary forms, with or without ;;;; modification, are permitted provided that the following conditions ;;;; are met: ;;;; 1. Redistributions of source code must retain the above copyright ;;;; notice, this list of conditions and the following disclaimer. ;;;; 2. Redistributions in binary form must reproduce the above copyright ;;;; notice, this list of conditions and the following disclaimer in the ;;;; documentation and/or other materials provided with the distribution. ;;;; 3. Neither the name of the author nor the names of the contributors ;;;; may be used to endorse or promote products derived from this software ;;;; without specific prior written permission. ;;;; ;;;; THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND ;;;; ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE ;;;; IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ;;;; ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE ;;;; FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL ;;;; DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS ;;;; OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) ;;;; HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT ;;;; LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY ;;;; OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF ;;;; SUCH DAMAGE. ;;;; ************************************************************************* (in-package #:cluck) (defvar *f-cpu* 16000000) (defvar *8-bit-prescalars* '(1 8 64 256)) (defvar *10-bit-prescalars* '(1 8 64 256 1024)) (defvar *base-error-zero-baud-clk* (* 9 25 8192) "Base multiple for multi-megahertz clock frequencies to have 0% error at common UART baud rates. Value of this base is 1.8432 million. Common multiples of this are 2 (3.6864Mhz), 4 (7.3728Mhz), 8 (14745600), and 10 (18.432MHz)") (defun show-timers (f-cpu prescalers width) (let ((max-count (expt 2 width))) (format t "~&Prescalar MaxRate MinUS MinRate MaxMS~%") (dolist (prescale prescalers) (let ((base (/ f-cpu prescale))) (format t "~4D ~12,1F ~9,3F ~10,4F ~13,3F~%" prescale (coerce base 'float) (coerce (/ 1000000 base) 'float) (coerce (/ base max-count) 'float) (coerce (/ 1000 (/ base max-count)) 'float)))))) (defun show-8-bit-timers (&optional (f-cpu *f-cpu*)) (show-timers f-cpu *10-bit-prescalars* 8)) (defun show-16-bit-timers (&optional (f-cpu *f-cpu*)) (show-timers f-cpu *10-bit-prescalars* 16)) (defun show-32-bit-timers (&optional (f-cpu *f-cpu*)) "Show max/min periods for 32-bit timers. For 16-bit PIC controllers, 32-bit timers use 8-bit prescalers" (show-timers f-cpu *8-bit-prescalars* 32)) (defun ms-timer-width (ms f-cpu prescalars width) "Returns the prescalar and compare count for both 8 and 16 bit timers." (labels ((nearest-count (prescale) (let ((count (round (* ms (/ f-cpu 1000 prescale)))) (max-count (expt 2 width))) (cond ((< count 1) 1) ((<= count max-count) count) ((> max-count) max-count)))) (clk-ms (prescale count) (unless (zerop count) (/ count (/ f-cpu 1000 prescale)))) (percent-error (actual desired) (* 100 (- (/ actual desired) 1)))) (dolist (prescale prescalars) (let* ((count (nearest-count prescale)) (clk-ms (clk-ms prescale count)) (err (percent-error clk-ms ms)) (fmt-err (if (> err 1000) " >1000%" (format nil "~8,3F%" err)))) (format t "~2D ~4D ~5D ~10,4F ~A~%" width prescale count clk-ms fmt-err))))) (defun ms-timer (ms &optional (f-cpu *f-cpu*)) "Returns the prescalar and compare count for both 8 and 16 bit timers." (dolist (width '(8 16)) (ms-timer-width ms f-cpu *10-bit-prescalars* width))) (defconstant* +baud-rates+ '(300 600 1200 2400 4800 9600 14400 19200 28800 38400 56000 57600 76800 115200 128000 250000 256000 500000)) (defun avr-uart-divisors (&optional (f-cpu *f-cpu*) (view-below-percent nil)) "Displays the divisor UBRR and error percent for various baud rates for F_CPU. UBBR is limited to 12 bits." (dolist (baud +baud-rates+) (let* ((ubrr (min 4096 (max 0 (round (- (/ f-cpu 16 baud) 1))))) (ubrr2 (min 4096 (max 0 (round (- (/ f-cpu 8 baud) 1))))) (actual-baud (/ f-cpu 16 (1+ ubrr))) (actual-baud2 (/ f-cpu 8 (1+ ubrr2))) (err (* 100 (- (/ actual-baud baud) 1))) (err2 (* 100 (- (/ actual-baud2 baud) 1)))) (when (or (not view-below-percent) (or (< (abs err) view-below-percent) (< (abs err2) view-below-percent))) (format t "~6D ~4D ~5,1F% ~4D ~5,1F%~%" baud ubrr err ubrr2 err2))))) (defun pic-uart-divisors (&optional (fcy *f-cpu*) (view-below-percent nil)) "Displays the divisor BRG and error percent for various baud rates for Fcy. BRG is limited to 16 bits." (dolist (baud +baud-rates+) (let* ((brg (min 65536 (max 0 (round (- (/ fcy 16 baud) 1))))) (actual-baud (/ fcy 16 (1+ brg))) (err (* 100 (- (/ actual-baud baud) 1)))) (when (or (not view-below-percent) (< (abs err) view-below-percent)) (format t "~6D ~4D ~5,1F%~%" baud brg err))))) (defun zero-error-uart-clocks () (dolist (mult '(1 2 4 6 8 10 12)) (format t "~&~8,4F MHz~%" (* mult *base-error-zero-baud-clk* 1e-6))))