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Basic Information
Question 1
Does the HT82M9AE contain an RC Oscillator?
Answer
The HT82M9AE does not contain an RC Oscillator, only a 6MHz or 12MHz crystal oscillator is provided.
Functional Description
Question 1
How is the HT82M9AE/HT82M9BE setup in either the USB Mode or the PS/2 Mode?
Answer
The working mode of the HT82M9AE/HT82M9BE can be setup via the SELPS2(bit4) and SELUSB(bit5) bits in the USR register (0x1B). When SELPS2 is 1 and SELUSB is 0, then the MCU will be in the PS2 Mode. When SELUSB is 1 and SELPS2 is 0, the MCU will be in the USB Mode.
Question 2
How can the Remote Wake-up function on the HT82M9AE/HT82M9BE be setup?
Answer
The USB Remote Wake-up function is controlled by bit 0 in the AWR register. If this bit is set to 1, then the function is active, if the bit is 0 then the function is inactive.
Question 3
How are the different banks in the Data Memory, Bank 0 and Bank 1, in the HT82M9AE/HT82M9BE accessed?
Answer
The Data Memory in the HT82M9AE/HT82M9BE is subdivided into two banks, Bank 0 and Bank 1.
1. Bank 0 and Bank 1 in the memory range 00H-1FH, both address the same registers, which are the special purpose registers.
2. Bank 0 has another function for General Purpose Data Memory in the range from 20H-FFH
3. Bank 1 has other special registers for the USB function, for the HT82M9AE this range is from 41H-4AH and for the HT82M9BE the range is from 41H-4BH.
4. Bank 0 can be accessed use both direct and indirect addressing methods, while Bank 1 can only be accessed using indirect addressing methods. Indirect addressing needs to use the memory pointers MP0 and MP1. The memory pointer MP0 will ignore any Bank Pointer, BP, setting and will only address Bank 0, however the memory pointer MP1 will address the Bank selected by the Bank Pointer. Setting the Bank Pointer to 0 or 1 will address either Bank 0 or Bank 1 respectively. Bank 1 can only be accessed using MP1 after BP has been set to 1.
Question 4
What points should be noted when choosing the clock frequency on the HT82M99E/HE82M99A?
Answer
The HT82M99E/HE82M99A operate with a clock frequency of 6MHz or 12MHz. The SCLKSEL bit in the SCC register must be setup correctly to reflect the clock frequency. For the 12MHz clock the SCLKSEL bit should be set to 0, while for the 6MHz clock the SCLKSEL bit should be set to 1.
Basic Information
Question 1
For the HT82M99E/HT82M99A devices what kinds of USB signal will generate a USB interrupt?
Answer
When using the USB interrupts, the following USB signals will generate a USB interrupt:
1. USB Suspend. When the main controller sends a suspend signal, the USC register SUSPEND bit, which is bit 0, will be set and an interrupt generated.
2. USB Resume. When the main controller send a resume signal, the USC register RESUME bit, which is bit 3, will be set and an interrupt generated.
3. USB Reset. When a USB reset signal is detected, the USC register URST_FLAG, which is bit 2, bit will be set and an interrupt generated.
4. USB Read/Write Endpoint. When the main controller read or writes an endpoint, the USR register EP01F bit, which is bit 0, or the EP1IF bit, which is bit 1, will be set and an interrupt generated
The above flags will be reset by the firmware during interrupt handling.
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