MC9328MX21S Datasheet, PDF (4/88 Pages) Freescale Semiconductor, Inc – MX family of microprocessors

Signal Descriptions
— Three Universal Asynchronous Receiver/Transmitters (UARTx)
— Two Configurable Serial Peripheral Interfaces (CSPIx) for High Speed Data Transfer
— Inter-IC (I²C) Bus Module
— Two Synchronous Serial Interfaces (SSI) with Inter-IC Sound (I²S)
— Digital Audio Mux
— One-Wire Controller
— Keypad Interface
• Memory Expansion and I/O Card Support
— Two Multimedia Card and Secure Digital (MMC/SD) Host Controller Modules
• Memory Interface
— External Interface Module (EIM)
— SDRAM Controller (SDRAMC)
— NAND Flash Controller (NFC)
— PCMCIA/CF Interface
• Standard System Resources
— Clock Generation Module (CGM) and Power Control Module
— Three General-Purpose 32-Bit Counters/Timers
— Watchdog Timer
— Real-Time Clock/Sampling Timer (RTC)
— Pulse-Width Modulator (PWM) Module
— Direct Memory Access Controller (DMAC)
— General-Purpose I/O (GPIO) Ports
— Debug Capability
2 Signal Descriptions
Table 2 identifies and describes the i.MX21S signals. Pin assignment is provided in Section 4, “Pin
Assignment and Package Information” and in the “Signal Multiplexing Scheme” table within the reference
manual.
The connections of the pins in Table 2 depends solely upon the user application, however there are a few
factory test signals that are not used in a normal application. Following is a list of these signals and how
they are to be terminated for proper operation of the i.MX21S processor:
• CLKMODE[1:0]: To ensure proper operation, leave these signals as no connects.
• OSC26M_TEST: To ensure proper operation, leave this signal as no connect.
• EXT_48M: To ensure proper operation, connect this signal to ground.
• EXT_266M: To ensure proper operation, connect this signal to ground.
• TEST_WB[2:0]: These signals are also multiplexed with GPIO PORT E as well as alternate
keypad signals. If not utilizing these signals for GPIO functionality or for their other multiplexed
function, then configure as GPIO input with pull up enabled, and leave as a no connect.
• TEST_WB[4:3]: To ensure proper operation, leave these signals as no connects.
MC9328MX21S Technical Data, Rev. 1.1
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Freescale Semiconductor