F²MC-8FX FAMILY MB95200H/210H SERIES HOW TO DO CR TRIMMING 8-BIT MICROCONTROLLER APPLICATION NOTE

Transcription

1 Fujitsu Microelectronics (Shanghai) Co., Ltd Application Note MCU-AN E-10 F²MC-8FX FAMILY 8-BIT MICROCONTROLLER MB95200H/210H SERIES HOW TO DO CR TRIMMING APPLICATION NOTE

2 CR trimming Operation V1.0 Revision History Revision History Date Author Change record Raven Peng V1.0 First draft This document contains 11 pages. 1. The products described in this manual and the specifications thereof may be changed without prior notice. To obtain up-to-date information and/or specifications, contact your Fujitsu sales representative or Fujitsu authorized dealer. 2. Fujitsu will not be liable for infringement of copyright, industrial property right, or other rights of a third party caused by the use of information or drawings described in this manual. 3. The contents of this manual may not be transferred or copied without the express permission of Fujitsu. 4. The products contained in this document are not intended for use with equipments which require extremely high reliability such as aerospace equipments, undersea repeaters, nuclear control systems or medical equipment for life support. 5. Some of the products described in this manual may be strategic materials (or special technology) as defined by the Foreign Exchange and Foreign Trade Control Law. In such cases, the products or portions theory must not be exported without permission as defined under the law Fujitsu Microelectronics (Shanghai) Co., Ltd MCU-AN E-10 Page 2

3 CR trimming operation V1.0 Contents Contents REVISION HISTORY... 2 CONTENTS INTRODUCTION MAIN CR OSCILLATOR DESCRIPTION General CR Oscillator Control CR Control Register CR TRIMMING PROCESS Why Need CR Trimming Process CR Trimming Controlled by BGM Adapter The Format of CR Trimming Command CR Status Check CR Trimming Process Simple Flowchart of CR Trimming Process CR Trimming Result Dialogs Precautions on CR Trimming Result ADVANCED OPERATION AFTER CR TRIMMING Measure the CR Frequency CR Clock Repair FIGURES: MCU-AN E-10 Page 3

4 CR trimming Operation V1.0 Chapter 1 Introduction 1 Introduction This application note describes the main CR clock configuration and the CR trimming function. MCU-AN E-10 Page 4

5 CR trimming operation V1.0 Chapter 2 Main CR Oscillator Description 2 Main CR Oscillator Description Describe the configuration of CR Oscillator 2.1 General MB95F200/210 series MCU contains internal main CR oscillator; the CR oscillator can provide Main CR clock to MCU. The frequency of CR oscillator is controlled by CR control register. The basic frequency of the CR oscillator is set to 1MHz when leave factory. The CR oscillator also can provide multiple frequencies 8MHz/10MHz/12.5MHz to main CR clock. (See figure 2.2-1) 2.2 CR Oscillator Control The following block diagram shows the CR oscillator interface. Figure 2.2-1: Main CR clock construction CRTH [4:0] and CRTL [4:0] are used to tune the frequency of CR oscillator. CRTH [6:5] is used to control the output of CR oscillator to main CR clock. CRTH [4:0] can tune CR frequency coarsely (step length: -20KHz~-8KHz); CRTL [4:0] can tune CR frequency finely (step length: -8KHz~-1.6KHz). And generally the basic CR frequency can be set from 1.9MHz to 400KHz. When CRTH [4:0] and CRTL [4:0] are set to 00000B, CR oscillator is tuned at the fastest frequency. When CRTH [4:0] and CRTL [4:0] are set to 11111B, CR oscillator is tuned at the slowest frequency. CRTH [6:5] is set to 11B when leave factory, so the initial frequency of main CR clock is 8MHz. MCU-AN E-10 Page 5

6 2.3 CR Control Register CR trimming Operation V1.0 Chapter 2 Main CR Oscillator Description CR control register is a CRTH and CRTL "CR Clock Trimming Register". CR oscillator needs to keep 1MHz frequency for debug usage. (See chapter 3) so CRTH and CRTL are used NON-Volatile register construction. The following block diagram shows the CRTH and CRTL interface. Figure 2.3-1: NVR registers construction During reset, data in NVR will be fetched from flash area and stored into IO area. So if user modified CRTH and CRTL in IO area, the value could be recovered after reset. CRTH [4:0] and CRTL [4:0] in Flash area are reserved to user. Write code or constant data to CRTH [4:0] and CRTL [4:0] has no effective. So if set const section in user code as follow, CRTH [4:0] and CRTL [4:0] are also keep their original value; could not be changed to 0808H..section NVR,CONST,LOCATE=H FFBC.DATA.W 0x0808 // set CRTH & CRTL But CRTH [6:5] can be modified by user. MCU-AN E-10 Page 6

7 CR trimming operation V1.0 Chapter 3 CR Trimming Process 3 CR Trimming Process CR TRIMMING PRINCIPLE 3.1 Why Need CR Trimming Process. The CR trimming function is used by BGM adapter to control the CR frequency by adjust CR control register. In debug mode, CR oscillator is used to generate 62500bps baud rate signal to support 1- line UART communication. And the baud rate setting is base on 1MHz CR frequency. If the frequency of CR clock is out of range: 1MHz±3.75%, target MCU will lose communication with BGM Adapter. Debug will be stopped. To start debug, BGM Adapter needs to know the CR clock status; and also needs to adjust CR frequency if once the CR frequency is changed. Then BGM adapter start CR trimming process after target MCU power on. 3.2 CR Trimming Controlled by BGM Adapter The Format of CR Trimming Command BGM Adapter sends two bytes (0x55AA) to target MCU as CR trimming command. There is an interval (3.5ms) between 0x55 and 0xAA. Then BGM Adapter waits some time (2.7ms) for the ACK (1 byte) from target MCU. Repeat the command for CR status check and CR trimming. 0x55 <<interval>> 0xAA <<wait for ACK>> 0x55 <<interval>> 0xAA CR Status Check BGM Adapter checks the CR clock status after each time detects target MCU power on. First, BGM Adapter attempts to send trimming command 10 times after detected target MCU power on. If BGM Adapter receives right ACK (data 51H ) from target MCU in this 10 times commands, BGM Adapter will indicate CR_OK to Softune. If BGM Adapter receives wrong ACK (other data than 51H ) from target MCU in this 10 times commands, BGM Adapter will indicate TRIM_FAIL to Softune. If there is no ACK received by BGM Adapter in this 10 times commands, BGM Adapter will start CR trimming process to adjust CR frequency. (See chapter 3.2.3) CR Trimming Process To do CR trimming process, BGM Adapter continues to send trimming commands to target MCU until receive ACK or retry times are out of range (CR trimming fail). If NVR is broken in target MCU, target MCU gets wrong CR frequency after power on. Then target MCU can t receive trimming command correctly. After receive trimming command with frame error for several times, target MCU starts to do CR trimming. Target MCU sets CRTH [4:0] and CRTL [4:0] to 00000B and wait for trimming command, after receives wrong command each time, target MCU increases the value of CRTH [4:0] and CRTL [4:0] as a regulation. If receives the right trimming command, target MCU will do a little adjustment then return A1H to BGM Adapter as ACK. MCU-AN E-10 Page 7

8 CR trimming Operation V1.0 Chapter 3 CR Trimming Process If BGM Adapter receives ACK (data A1H ) from target MCU during CR trimming, BGM Adapter will indicate TRIM_OK to Softune. In normal case, the CR frequency can be adjusted to 1MHz±3% in this situation. And the precision can insure 1-line UART communication. If CR trimming process fails, BGM Adapter will indicate TRIM_FAIL to Softune Simple Flowchart of CR Trimming Process The following diagram is the simple CR trimming flowchart based on BGM Adapter side. Figure : CR trimming flowchart MCU-AN E-10 Page 8

9 CR trimming operation V1.0 Chapter 3 CR Trimming Process 3.3 CR Trimming Result Dialogs. Softune will check the CR clock status and show the result to user when start debug: If CR frequency is OK, Softune will continue debug normally. If CR trimming process passed, Softune will show the following dialog: Figure 3.3-1: means CR trimming passed If CR trimming process failed, Softune will show the following dialog: Figure 3.3-2: means NVR is broken and CR trimming failed If BGM Adapter is busy in doing CR trimming process. Softune will show the following dialog until CR trimming process finish: Figure 3.3-3: means CR trimming is in process 3.4 Precautions on CR Trimming Result. If target MCU runs in free-run mode, BGM Adapter may receive no response from target MCU, then BGM Adapter will indicate TRIM_FAIL to Softune. If target MCU runs in debug mode, and BGM Adapter reset at once, then BGM Adapter may indicate TRIM_FAIL to Softune too. So if CR trimming process failed, please re-connect debug tools and try again firstly. If CR trimming process failed for several times, that means target MCU is broken. If CR trimming process passed, the CR clock maybe can not support very accurate 1MHz frequency. But it is not influence the 1-line UART communication. If accurate CR frequency is needed in application, please contact to the shop that bought it or adjust CR trimming value according to next chapter. MCU-AN E-10 Page 9

10 CR trimming Operation V1.0 Chapter 4 Advanced operation after CR Trimming 4 Advanced operation after CR Trimming ADVANCED OPERATION OF CR Trimming 4.1 Measure the CR Frequency. Use compound timer output CR clock to an I/O port (E.g. 8MHz/8) in user code, then the CR frequency is measurable. Change CR trimming value in user code couldn t modify the CR trimming value in flash area. But this operation may cause the user code only can be run in free-run mode. 4.2 CR Clock Repair. After CR trimming process, the precision of CR frequency may change to 1MHz±3%. If the precision is not enough, you can repair CR clock manually. The process is: When start debug with a dedicated target MCU at the first time, record the value of CR control register (flash area) of this MCU. (The value can be read in memory window.) If the CR frequency is not very near 1MHz after CR trimming process, please modify the CR control register (I/O area) to the same value as recorded before. After Softune download program to flash memory, the value of CR control register in flash area will be repaired. MCU-AN E-10 Page 10

11 CR trimming operation V1.0 Figures: Figures: Figure 2.2-1: Main CR clock construction... 5 Figure 2.3-1: NVR registers construction... 6 Figure : CR trimming flowchart... 8 Figure 3.3-1: means CR trimming passed... 9 Figure 3.3-2: means NVR is broken and CR trimming failed... 9 Figure 3.3-3: means CR trimming is in process... 9 MCU-AN E-10 Page 11