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stv0910_utils.c
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stv0910_utils.c
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/* -------------------------------------------------------------------------------------------------- */
/* The LongMynd receiver: stv0910_utils.c */
/* - an implementation of the Serit NIM controlling software for the MiniTiouner Hardware */
/* - These routines abstract the register read and writes for the demodulator (STV0910) */
/* Copyright 2019 Heather Lomond */
/* -------------------------------------------------------------------------------------------------- */
/*
This file is part of longmynd.
Longmynd is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
Longmynd is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with longmynd. If not, see <https://www.gnu.org/licenses/>.
*/
/* -------------------------------------------------------------------------------------------------- */
/* ----------------- INCLUDES ----------------------------------------------------------------------- */
/* -------------------------------------------------------------------------------------------------- */
#include <stdio.h>
#include <stdint.h>
#include "stv0910_regs.h"
#include "stv0910_utils.h"
#include "errors.h"
#include "nim.h"
/* in order to do bitfields efficiently, we need to keep a shadow register set */
uint8_t stv0910_shadow_regs[STV0910_END_ADDR - STV0910_START_ADDR + 1];
/* -------------------------------------------------------------------------------------------------- */
/* ----------------- ROUTINES ----------------------------------------------------------------------- */
/* -------------------------------------------------------------------------------------------------- */
/* -------------------------------------------------------------------------------------------------- */
uint8_t stv0910_write_reg_field(uint32_t field, uint8_t field_val) {
/* -------------------------------------------------------------------------------------------------- */
/* changes a bitfield of a register using a shadow register array to do the read/modify/write */
/* field: the #define of the bitfield as given in stv0910_regs.h (from the datasheet) */
/* field_val: what to set the field to (in the LSBs of the value */
/* return: error code */
/* -------------------------------------------------------------------------------------------------- */
uint8_t err=ERROR_NONE;
uint16_t reg;
uint8_t val;
/* firsr we need to work out which register to use */
reg=field >> 16;
/* now we calculate the new value for this reg by reading the shadow array, */
/* masking out the field we want, and putting the new value in */
val=((stv0910_shadow_regs[reg-STV0910_START_ADDR] & ~(field & 0xff)) |
(field_val << ((field >> 12) & 0x0f)) );
/* now we can write the new value back to the demodulator and the shadow registers */
if (err==ERROR_NONE) err=nim_write_demod(reg, val);
if (err==ERROR_NONE) stv0910_shadow_regs[reg-STV0910_START_ADDR]=val;
if (err!=ERROR_NONE) printf("ERROR: STV0910 write field\n");
return err;
}
/* -------------------------------------------------------------------------------------------------- */
uint8_t stv0910_read_reg_field(uint32_t field, uint8_t *field_val) {
/* -------------------------------------------------------------------------------------------------- */
/* reads a bitfield of a register. This cannot go via the shadows as the regs are volatile */
/* field: the #define of the bitfield as given in stv0910_regs.h (from the datasheet) */
/* *field_val: the contents of the field once read */
/* return: error code */
/* -------------------------------------------------------------------------------------------------- */
uint8_t err=ERROR_NONE;
uint8_t val;
/* we can read the register value first */
if (err==ERROR_NONE) err=nim_read_demod((uint16_t)(field >> 16), &val);
/* and then do the masks and shifts to get at the specific bits */
*field_val = ((val) & (field & 0xff)) >> ((field >> 12) & 0x0f);
if (err!=ERROR_NONE) printf("ERROR: STV0910 read field\n");
return err;
}
/* -------------------------------------------------------------------------------------------------- */
uint8_t stv0910_write_reg(uint16_t reg, uint8_t val) {
/* -------------------------------------------------------------------------------------------------- */
/* abstracts a hardware register write to the stv0910 */
/* return: error code */
/* -------------------------------------------------------------------------------------------------- */
stv0910_shadow_regs[reg-STV0910_START_ADDR]=val;
return nim_write_demod(reg, val);
}
/* -------------------------------------------------------------------------------------------------- */
uint8_t stv0910_read_reg(uint16_t reg, uint8_t *val) {
/* -------------------------------------------------------------------------------------------------- */
/* abstracts a hardware register read from the stv0910 */
/* return: error code */
/* -------------------------------------------------------------------------------------------------- */
return nim_read_demod(reg, val);
}