MSPM0 SMBus Library User’s Guide

1. Introduction

The MSPM0 SMBus Library provides a simple way to start development of SMBus applications using MSPM0 devices.

2. SMBus Library Supported Features

This library was developed in compliance with the SMBus 3.2 specification.

2.1 SMBus Controller Supported Features

• Clock Timeout detection

• PEC

• Quick command

• Send Byte

• Receive Byte

• Write byte/word (support for 16bit, 32bit, and 64bit words)

• Read byte/word (support for 16bit, 32bit, and 64bit words)

• Process call

• Block read/write (up to 255 bytes)

• Block write-block read process call (up to 255 bytes)

• Host notify protocol

2.2 SMBus Target Supported Features

• Multiple target addresses

• Clock Timeout detection

• PEC

• Quick command (only write is supported)

• Send Byte

• Receive Byte

• Write byte/word (support for 16bit, 32bit, and 64bit words)

• Read byte/word (support for 16bit, 32bit, and 64bit words)

• Process call

• Block read/write (up to 255 bytes)

• Block write-block read process call (up to 255 bytes)

• Host notify protocol

2.3 SMBus Features Not Currently Implemented

The SMBus features listed below are supported in hardware but have not been implemented in this release:

• FastMode+ 1MHz operation

• Address resolution protocol

• SMBAlert#

• SMBSUS#

3. SMBus Example Usage

This software library contains 4 examples that demonstrate communication between a SMBus Controller and SMBus Target:

• Target:

  • smb_target00_all_protocols: shows the implementation of all basic SMBus protocols

  • smbus_target_host_notify: shows implementation of host notify protocol

• Controller:

  • smb_controller00_all_protocols: shows the implementation of all basic SMBus protocols

  • smbus_controller_host_notify: shows implementation of host notify protocol

Each example contains source code which can be compiled and loaded onto a supported device as-is. Connect SMBCLK and SMBDAT on 2 devices running the Controller and Target examples.

3.1 SMBus Examples Supported Hardware

• LP-MSPM0L1306 LaunchPad evaluation boards

• LP-MSPM0G3507 LaunchPad evaluation boards

4. SMBus Library API Guide

Details about the SMBus Library APIs can be found in the SMBus Library API Guide

5. Library Footprint

The following footprint was obtained with TI Arm Clang compiler v3.2.1 LTS using LP-MSPM0G3507.

SMBus Controller

Example	Module	Optimization Level	Code (bytes)	Const (bytes)	RAM (bytes)	Options
smb_controller00_all_protocols	Total	-O2	3912	469	1086	SMB_CONTROLLER_SUPPORTS_HOST_NOTIFY = true
“	smbus_nwk.o	“	1286	0	0	“
“	smbus_phy.o	“	948	0	0	“
“	smbus.o	“	572	0	0	“
“	dl_i2c.o	“	192	0	0	“
smb_controller00_all_protocols	Total	-Oz -flto*	3236	493	1088	SMB_CONTROLLER_SUPPORTS_HOST_NOTIFY = true
smb_controller00_all_protocols	Total	-O2	3272	469	1086	SMB_CONTROLLER_SUPPORTS_HOST_NOTIFY = false
“	smbus_nwk.o	“	804	0	0	“
“	smbus_phy.o	“	790	0	0	“
“	smbus.o	“	572	0	0	“
“	dl_i2c.o	“	192	0	0	“
smb_controller00_all_protocols	Total	-Oz -flto*	2714	493	1088	SMB_CONTROLLER_SUPPORTS_HOST_NOTIFY = false
smb_controller_host_notify	Total	-O2	3702	239	826	SMB_CONTROLLER_SUPPORTS_HOST_NOTIFY = true
“	smbus_nwk.o	“	1168	0	0	“
“	smbus_phy.o	“	968	0	0	“
“	smbus.o	“	228	0	0	“
“	dl_i2c.o	“	192	0	0	“
smb_controller_host_notify	Total	-Oz -flto*	2962	219	827	SMB_CONTROLLER_SUPPORTS_HOST_NOTIFY = true

• Note: Individual modules are not shown for LTO optimization since the linker optimizes modules and might skip them in .map file.

SMBus Target

Example	Module	Optimization Level	Code (bytes)	Const (bytes)	RAM (bytes)	Options
smb_target00_all_protocols	Total	-O2	5320	387	1343	SMB_TARGET_SUPPORTS_HOST_NOTIFY = true
“	smbus_nwk.o	“	1070	0	0	“
“	smbus_phy.o	“	900	0	0	“
“	smbus.o	“	252	0	0	“
“	dl_i2c.o	“	228	0	0	“
smb_target00_all_protocols	Total	-Oz -flto*	3908	387	1346	SMB_TARGET_SUPPORTS_HOST_NOTIFY = true
smb_target00_all_protocols	Total	-O2	4508	387	1343	SMB_TARGET_SUPPORTS_HOST_NOTIFY = false
“	smbus_nwk.o	“	716	0	0	“
“	smbus_phy.o	“	536	0	0	“
“	smbus.o	“	252	0	0	“
“	dl_i2c.o	“	134	0	0	“
smb_target00_all_protocols	Total	-Oz -flto*	3266	387	1346	SMB_TARGET_SUPPORTS_HOST_NOTIFY = false
smb_target_host_notify	Total	-O2	4110	245	1080	SMB_TARGET_SUPPORTS_HOST_NOTIFY = true
“	smbus_nwk.o	“	1142	0	0	“
“	smbus_phy.o	“	1124	0	0	“
“	smbus.o	“	262	0	0	“
“	dl_i2c.o	“	288	0	0	“
smb_target_host_notify	Total	-Oz -flto*	4110	245	1080	SMB_TARGET_SUPPORTS_HOST_NOTIFY = true

• Note: Individual modules are not shown for LTO optimization since the linker optimizes modules and might skip them in .map file.

6. Library Versions

• Version 2.00.00.00

  • SDK Release: 2.00.00.xx

  • Updates:

    • Fix Target PEC check. Device will NACK if PEC is incorrect and detect if PEC is missing. This feature causes a compatibility break.

• Version 1.30.00.01

  • SDK Release: 1.30.00.xx

  • Updates:

    • Added target reset function.

    • Added manual ACK support and modified ISR handling to avoid race condition issue with multiple interrupt flags.

    • Updated examples to use LED for error detection.

    • Added case to handle Controller TX flag when idle.

    • Added SW timeout to avoid lockup while polling flag.

    • Added compiler flags for Host Alert functionality.

• Version 1.20.00.01

  • SDK Release: 1.20.00.xx

  • Updates:

    • Updated code examples to use I2C BoosterPack pins.

    • Renamed existing SMBus examples to *00_all_protocols.

    • Added SMBus Host Alert for Controller and Target with corresponding examples.

    • Fixed some incorrect pins in the SMBus READMEs.

• Version 1.10.00.00

  • SDK Release: 1.10.00.xx

  • Updates:

    • Updated SMBus library to replace SW PEC with HW PEC.

• Version 1.00.00.00

  • SDK Release: 1.00.00.xx

  • Updates:

    • Initial release.

6.1 Upgrade and Compatibility Information

• Version 2.00.00.00

  • Application must now report command length to SMBus drivers when enabling PEC.

    • The application should call SMBus_targetReportBlock and/or SMBus_targetReportLength when the SMBus is in SMBus_State_Target_FirstByte state. See SMBus target examples for a sample implementation.

  • SMBus Target PEC error interrupt should be disabled. This flag is checked manually by the library during reception.

    • When using SysConfig, this option can be disabled at Interrupt Configuration → Target Interrupts.