Cypress FR81S CY91520 Series, Recommendation For Hardware Setup

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Document No. 002-09375 Rev. *B 1
AN209375
Recommendation for Hardware Setup 32-Bit FR81S Family
This application note describes how to set up a hardware environment for Cypress FR81S MCUs. As an example, the
CY91F52x MCU is used.
Contents
1 Introduction .................................................................. 1
2 Minimal System ........................................................... 2
2.1 Schematic ........................................................... 2
2.2 Serial Interface .................................................... 2
2.3 Power supply ...................................................... 2
2.4 Analog Digital Converter Supply Pins ................. 2
2.5 Analog Input Pins ................................................ 3
2.6 Reset Pin (RSTX) ............................................... 4
2.7 Non maskable Interrupt Pin (NMIX) .................... 4
2.8 C-Pin ................................................................... 5
2.9 Clock Source ....................................................... 5
2.10 Mode Pins ........................................................... 6
2.11 Not Connected Pins ............................................ 6
2.12 Debug Interface connection ................................ 7
3 Layout and Electromagnetic Compatibility ................... 8
3.1 General ............................................................... 8
3.2 Power supply Pins .............................................. 8
3.3 Oscillator Pins ..................................................... 9
3.4 Power Line Routing ............................................. 9
3.5 Power Supply Decoupling ................................. 10
3.6 Recommended Power Supply Circuit ............... 12
3.7 Reset circuit ...................................................... 13
3.8 Quartz Crystal Placement and Signal Routing .. 16
3.9 Test points ........................................................ 18
3.10 Other documents .............................................. 18
4 Port Input / Unused Pins / Latch-up ........................... 19
4.1 Port Input / Unused Pins ................................... 19
4.2 Latch-up consideration (switch) ........................ 20
4.3 5 V Tolerant Input pins ...................................... 24
5 Flash Programming Connection ................................ 25
5.1 Overview ........................................................... 25
5.2 Serial programming via UART0 ........................ 25
5.3 Serial programming via MDI interface ............... 27
5.4 Parallel programming interface ......................... 29
5.5 Security function ............................................... 29
6 Reset Behavior of IO port pins .................................. 30
7 Additional Information ................................................ 30
Worldwide Sales and Design Support ............................. 32
Cypress Developer Community....................................... 32
Technical Support ........................................................... 32
1 Introduction
This design guide describes design restrictions and recommendations regarding signal wiring and the electrical power
system of the MCU. For more details about the device features and its relevant settings, please refer to the FR81S
Hardware Manual and its corresponding Datasheet for electrical characteristics.