lpc43xx_scu.c

00001 /**
00002  * @file    lpc43xx_scu.c
00003  * @brief   
00004  *
00005  * DAPLink Interface Firmware
00006  * Copyright (c) 2009-2016, ARM Limited, All Rights Reserved
00007  * SPDX-License-Identifier: Apache-2.0
00008  *
00009  * Licensed under the Apache License, Version 2.0 (the "License"); you may
00010  * not use this file except in compliance with the License.
00011  * You may obtain a copy of the License at
00012  *
00013  * http://www.apache.org/licenses/LICENSE-2.0
00014  *
00015  * Unless required by applicable law or agreed to in writing, software
00016  * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
00017  * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
00018  * See the License for the specific language governing permissions and
00019  * limitations under the License.
00020  */
00021 
00022 /* Includes ------------------------------------------------------------------- */
00023 #include "LPC43xx.h"                      /* lpc43xx definitions                */
00024 #include "lpc_types.h"
00025 #include "lpc43xx_scu.h"
00026 
00027 /* Pin modes
00028 *  =========
00029 *  The EPUN and EPD bits in the SFS registers allow the selection of weak on-chip
00030 *  pull-up or pull-down resistors with a typical value of 50 kOhm for each pin or the
00031 *  selection of the repeater mode.
00032 *  The possible on-chip resistor configurations are pull-up enabled, pull-down enabled, or no
00033 *  pull-up/pull-down. The default value is pull-up enabled.
00034 *
00035 *  The repeater mode enables the pull-up resistor if the pin is at a logic HIGH and enables
00036 *  the pull-down resistor if the pin is at a logic LOW. This causes the pin to retain its last
00037 *  known state if it is configured as an input and is not driven externally. Repeater mode may
00038 *  typically be used to prevent a pin from floating (and potentially using significant power if it
00039 *  floats to an indeterminate state) if it is temporarily not driven.
00040 *  Repeater mode is enabled when both pull-up and pull-down are enabled.
00041 *
00042 *  To be able to receive a digital signal, the input buffer must be enabled through bit EZI in
00043 *  the pin configuration registers. By default, the input buffer is disabled.
00044 *  For pads that support both a digital and an analog function, the input buffer must be
00045 *  disabled before enabling the analog function.
00046 *
00047 *  All digital pins support a programmable glitch filter (bit ZIF), which can be switched on or
00048 *  off. By default, the glitch filter is on. The glitch filter should be disabled for
00049 *  clocking signals with frequencies higher than 30 MHz.
00050 *
00051 *  Normal-drive and high-speed pins support a programmable slew rate (bit EHS) to select
00052 *  between lower noise and low speed or higher noise and high speed . The typical
00053 *  frequencies supported are 50 MHz/80 MHz for normal-drive pins and 75 MHz/180 MHz for
00054 *  high-speed pins.
00055 */
00056 
00057 /*********************************************************************//**
00058  * @brief       Configure pin function
00059  * @param[in]   port    Port number, should be: 0..15
00060  * @param[in]   pin Pin number, should be: 0..31
00061  * @param[in]   mode    Pin mode, should be:
00062  *                  - MD_PUP    :Pull-up enabled
00063  *                  - MD_BUK    :Plain input
00064  *                  - MD_PLN    :Repeater mode
00065  *                  - MD_PDN    :Pull-down enabled
00066  *                  - MD_EHS        :Slew rate
00067  *                  - MD_EZI        :Input buffer enable
00068  *                  - MD_ZI         :Glitch filter enabled
00069  *                  - MD_EHD0       :High drive  8 mA
00070  *                  - MD_EHD1       :High drive 14 mA
00071  *                  - MD_EHD2       :High drive 20 mA
00072  * @param[in]   func    Function mode, should be:
00073  *                  - FUNC0     :Function 0
00074  *                  - FUNC1     :Function 1
00075  *                  - FUNC2     :Function 2
00076  *                  - FUNC3     :Function 3
00077  *                  - FUNC4     :Function 4
00078  *                  - FUNC5     :Function 5
00079  *                  - FUNC6     :Function 6
00080  *                  - FUNC7     :Function 7
00081  * @return      None
00082  **********************************************************************/
00083 void scu_pinmux(uint8_t port, uint8_t pin, uint8_t mode, uint8_t func)
00084 {
00085     uint32_t *scu_base = (uint32_t *)(LPC_SCU_BASE);
00086     scu_base[(PORT_OFFSET * port + PIN_OFFSET * pin) / 4] = mode + func;
00087 } /* scu_pinmux */