參數(shù)資料
型號: MC56F8355MFG60
廠商: MOTOROLA INC
元件分類: 數(shù)字信號處理
英文描述: 4-BIT, 120 MHz, OTHER DSP, PQFP128
封裝: LQFP-128
文件頁數(shù): 17/152頁
文件大小: 2224K
代理商: MC56F8355MFG60
Flash Access Blocking Mechanisms
56F8355 Technical Data
113
Preliminary
Proper implementation of Flash security requires that no access to the EOnCE port is provided
when security is enabled. The 56800E core has an input which disables reading of internal memory
via the JTAG/EOnCE. The FM sets this input at reset to a value determined by the contents of the
FM security bytes.
7.2.3
Flash LOCKOUT_RECOVERY
If a user inadvertently enables security on the 56F8355, a lockout recovery mechanism is provided
which allows the complete erasure of the internal Flash contents, including the configuration field,
and thus disables security (the protection register is cleared). This does not compromise security,
as the entire contents of the user’s secured code stored in Flash are erased before security is
disabled on the 56F8355 on the next reset or power-up sequence. To start the lockout recovery
sequence, the JTAG public instruction (LOCKOUT_RECOVERY) must first be shifted into the
chip-level TAP controller’s instruction register.
The LOCKOUT_RECOVERY instruction has an associated 7-bit Data Register (DR) that is used
to control the clock divider circuit within the FM module. This divider, FM_CLKDIV[6:0], is used
to control the period of the clock used for timed events in the FM erase algorithm. This register
must be set with appropriate values before the lockout sequence can begin. Refer to the JTAG
section of the 56F8300 Peripheral User Manual for more details on setting this register value.
The value of the JTAG FM_CLKDIV[6:0] will replace the value of the FM register FMCLKD that
divides down the system clock for timed events, as illustrated in Figure 7-1. FM_CLKDIV[6] will
map to the PRDIV8 bit, and FM_CLKDIV[5:0] will map to the DIV[5:0] bits. The combination of
PRDIV8 and DIV must divide the FM input clock down to a frequency of 150kHz-200kHz. The
“Writing the FMCLKD Register” section in the Flash Memory chapter of the 56F8300
Peripheral User Manual gives specific equations for calculating the correct values.
Figure 7-1 JTAG to FM Connection for LOCKOUT_RECOVERY
Two examples of FM_CLKDIV calculations follow.
JTAG
FMCLKD
DIVIDER
7
FM_CLKDIV
FM_ERASE
Flash Memory
clock
input
SYS_CLK
2
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相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
MC56F8355MFGE 功能描述:數(shù)字信號處理器和控制器 - DSP, DSC 16 BIT HYBRID CONTROLLER RoHS:否 制造商:Microchip Technology 核心:dsPIC 數(shù)據(jù)總線寬度:16 bit 程序存儲器大小:16 KB 數(shù)據(jù) RAM 大小:2 KB 最大時鐘頻率:40 MHz 可編程輸入/輸出端數(shù)量:35 定時器數(shù)量:3 設(shè)備每秒兆指令數(shù):50 MIPs 工作電源電壓:3.3 V 最大工作溫度:+ 85 C 封裝 / 箱體:TQFP-44 安裝風(fēng)格:SMD/SMT
MC56F8355VFG60 制造商:FREESCALE 制造商全稱:Freescale Semiconductor, Inc 功能描述:16-bit Hybrid Controllers
MC56F8355VFGE 功能描述:數(shù)字信號處理器和控制器 - DSP, DSC 16 BIT HYBRID CNTRLR RoHS:否 制造商:Microchip Technology 核心:dsPIC 數(shù)據(jù)總線寬度:16 bit 程序存儲器大小:16 KB 數(shù)據(jù) RAM 大小:2 KB 最大時鐘頻率:40 MHz 可編程輸入/輸出端數(shù)量:35 定時器數(shù)量:3 設(shè)備每秒兆指令數(shù):50 MIPs 工作電源電壓:3.3 V 最大工作溫度:+ 85 C 封裝 / 箱體:TQFP-44 安裝風(fēng)格:SMD/SMT
MC56F8356 制造商:MOTOROLA 制造商全稱:Motorola, Inc 功能描述:56F8356 16-bit Hybrid Controller
MC56F8356MFV60 制造商:Rochester Electronics LLC 功能描述:- Bulk